# NGK Spark Plug Dimensions: 8mm, 10mm, 12mm, 18mm & Racing Plugs ## NGK Spark Plug Dimensions: 8mm, 10mm, 12mm, 18mm & Racing Plugs 421 plugs. The physical dimensions of each plug in the NGK range: thread size, reach, hex, seat type and whether the tip is projected. This is what decides whether a plug will physically fit and seal, before heat range comes into it. **Plug codes are links — click one to go straight to that plug on our shop.** **Reach and seat type are not interchangeable.** A plug that is too long can hit the piston; one that is too short leaves thread exposed in the combustion chamber and will not transfer heat properly. A tapered-seat plug will not seal in a gasket-seat head. Match all of thread, reach and seat, then match the heat range. - [12mm Spark Plugs](#12mm-spark-plugs) - [10mm Spark Plugs](#10mm-spark-plugs) - [18mm Spark Plugs](#18mm-spark-plugs) - [8mm Spark Plugs](#8mm-spark-plugs) - [Racing Spark Plugs](#racing-spark-plugs) - [PF1/2S Spark Plugs](#pf1-2s-spark-plugs) - [Thread size not listed](#thread-size-not-listed) ### 12mm Spark Plugs 177 plugs NGK plug Range Reach Hex Seat Notes DCPR6EIX · [DCPR7EIX](/products/dcpr7eix-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [DCPR8EIX](/products/dcpr8eix-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [DCPR9EIX](/products/dcpr9eix-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · KR8DI Iridium 3/4" Reach 5/8" Hex Gasket, Loose Projected [DF6H-11A](/products/df6h-11a-ngk-iridium-double-fine-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 14mm Hex Gasket, Solid Extended Shell Extended Projection Wide Gap Dual Fine Electrode [DF8H-11B](/products/df8h-11b-ngk-iridium-double-fine-spark-plug-genuine-ngk-spark-plug) · [DILKR6D11G](/products/dilkr6d11g-ngk-iridium-double-fine-spark-plug-genuine-ngk-spark-plug) · DILKR7A11 Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Projected, Wide Gap Dual Fine Electrode [DILKAR6A11](/products/dilkar6a11-ngk-iridium-double-fine-spark-plug-genuine-ngk-spark-plug) · DILKAR7G11GS · DILKAR7H11GS Iridium 26.5mm Reach 14mm Hex Gasket, Solid Projected Wide Gap Dual Fine Electrode DILKAR7B8 · [DILKAR8A8](/products/dilkar8a8-ngk-iridium-double-fine-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 14mm Hex Gasket, Solid Projected Dual Fine Electrode [DILKAR7C9H](/products/dilkar7c9h-ngk-iridium-double-fine-spark-plug-genuine-ngk-spark-plug) Iridium 28.5mm Reach 14mm Hex Gasket, Solid Projected Dual Fine Electrode DILKR7B6 · [DILKR8B6](/products/dilkr8b6-ngk-iridium-double-fine-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Projected Dual Fine Electrode DILZKAR7B11 · [ILZKR7B11](/products/ilzkr7b11-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [ILZKR7B-11S](/products/ilzkr7b-11s-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Extended Projection Wide Gap DILZKAR7B11G · DILZKAR7C11S · DILZKR7A11G · [DILZKR7B11GS](/products/dilzkr7b11gs-ngk-iridium-double-fine-spark-plug-genuine-ngk-spark-plug) · DILZKR711DS Iridium 26.5mm Reach 5/8" Hex Gasket, Solid, Wide Extended Projection Extended Shell, DFE Gap DPR7EIX-9 · [DPR8EIX-9](/products/dpr8eix-9-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · DPR9EIX-9 · IJR7AP Iridium 3/4" Reach 18mm Hex Gasket, Stud Projected, Wide Gap DR7EIX · [DR8EIX](/products/dr8eix-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [DR9EIX](/products/dr9eix-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 3/4" Reach 18mm Hex Gasket, Stud IKR7H8 · KR8AI · KR8BI Iridium 3/4" Reach 5/8" Hex Gasket, Solid Projected 2-Ground Electrode ILKAR6C10 · [ILKAR7B11](/products/ilkar7b11-ngk-spark-plug) · [ILKAR7C10](/products/ilkar7c10-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [ILKAR7L11](/products/ilkar7l11-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · LKAR6AIX-11 · LKAR7BIX-11S · [LKAR8AI-9](/products/lkar8ai-9-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 14mm Hex Gasket, Solid Projected Wide Gap [ILKAR8H6](/products/ilkar8h6-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 14mm Hex Gasket, Solid Projected [ILKR7B8](/products/ilkr7b8-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · ILKR7E6 · [ILKR8E6](/products/ilkr8e6-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [ILKR8Q7](/products/ilkr8q7-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [ILKR9Q7G](/products/ilkr9q7g-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · LKR6CIX · LKR7AIX · SILKR8B8DS Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Projected [ILNAR8B7G](/products/ilnar8b7g-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · SILNAR7B7 · [SILZNAR6D9](/products/silznar6d9-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [SILZNAR8C7H](/products/silznar8c7h-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 25mm Reach 14mm Hex Projected Tapered Solid [ILZKAR7A10](/products/ilzkar7a10-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · ILZKAR7B11 Iridium 26.5mm Reach 14mm Hex Gasket, Solid Extended Projection Wide Gap ILZKAR8H8S · [ILZKAR8J8SY](/products/ilzkar8j8sy-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [ILZKR7A](/products/ilzkr7a-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [ILZKR8A](/products/ilzkr8a-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Extended Projected Extended Shell ILZKBR7B8DG · [SILZKBR8D8S](/products/silzkbr8d8s-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [SILZKBR8E8S](/products/silzkbr8e8s-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach Bi-Hex 14mm Gasket, Solid Extended Projection [ILZNAR8A7G](/products/ilznar8a7g-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 25 mm Reach 14 mm, Hex Extended Shell [IZKR7B](/products/izkr7b-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 3/4" Reach 5/8" Hex Gasket, Solid Extended Shell [KR9CI](/products/kr9ci-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 3/4" Reach 5/8" Hex Gasket, Solid Projected LKAR8BI9 · LKAR9BI9 · LKAR9BI-10 Iridium 26.5mm Reach 14mm Hex Gasket, Stud Projected Wide Gap LKR7BGP-S · LKR7DIX-11S Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Projected Wide Gap LZKR6AIX · SILKR8A-S · [SILZKR6B10E](/products/silzkr6b10e-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · SILZKR6B11 · SILZKR7B8E · [SILZKR7B11](/products/silzkr7b11-ngk-laser-iridium-spark-plug) · [SILZKR7E8EG](/products/silzkr7e8eg-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · SILZKR7E9G · SILZKR7E11 Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Extended Projection [SILZKAR7B11](/products/silzkar7b11-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 14mm Hex Gasket, Solid Extended Projection PSPE, Wide Gap [SILZKAR7E8S](/products/silzkar7e8s-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 14mm Hex Gasket, Solid Extended Shell Projected [SILZKFR8D7S](/products/silzkfr8d7s-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [SILZKFR8E7S](/products/silzkfr8e7s-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 14mm Hex Gasket, Solid Extended Shell Extended Projected [SILZKGR8B8S](/products/silzkgr8b8s-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · SILZKGR8C8S Iridium 26.5mm Reach Bi-Hex 14mm Gasket, Special Extended Projection Terminal SIZKBR8A8HS Iridium 23.7 mm Reach Bi-Hex, 14 mm Gasket, Solid Extended Shell Extended Projection SPE ZNAR6AIX-11 · ZNAR7AIX Iridium 26.5mm Reach 14mm Hex Tapered, Solid Extended Projection Wide Gap R2349-10 · R2349-11 NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid Surface Discharge Resistor R2525-9 · R2525-10 NGK Racing 3/4" Reach 5/8" Hex Gasket, Loose Platinum Resistor R2556B-8 · R2556B-9 · R2556B-10 · R2556G-8 · R2556G-9 · [R2556G-10](/products/r2556g-10-ngk-racing-spark-plug-genuine-ngk-spark-plug) · R2558E-9 NGK Racing 26.5mm Reach 5/8" Hex Gasket, Solid Iridium Resistor DCPR7EGP · [DCPR8EKP](/products/dcpr8ekp-ngk-platinum-spark-plug-genuine-ngk-spark-plug) · [PKR7A](/products/pkr7a-ngk-platinum-spark-plug-genuine-ngk-spark-plug) Platinum 3/4" Reach 5/8" Hex Gasket, Solid Projected 2-Ground Electrode LKAR6AGP · LKAR7AGP-D · LKAR7BGP-S · LKR6BGP-E Platinum 26.5mm Reach 14mm Hex Gasket, Solid Projected Wide Gap LKR7BGP-8 · PLKR6A · [PLKR7A](/products/plkr7a-ngk-platinum-spark-plug-genuine-ngk-spark-plug) · [PLKR7B8E](/products/plkr7b8e-ngk-platinum-spark-plug-genuine-ngk-spark-plug) Platinum 26.5mm Reach 5/8" Hex Gasket, Solid Projected [LKR8AP](/products/lkr8ap-ngk-platinum-spark-plug-genuine-ngk-spark-plug) Platinum 26.5mm Reach 5/8" Hex Gasket, Solid Projected 2-Ground Electrode LZKR6AGP-E Platinum 26.5mm Reach 5/8" Hex Gasket, Solid Extended Projection PJR7A Platinum 3/4" Reach 18mm Hex Gasket, Stud Projected [PLZKAR6A-11](/products/plzkar6a-11-ngk-platinum-spark-plug-genuine-ngk-spark-plug) Platinum 26.5mm Reach 14mm Hex Gasket, Solid Extended Projection Wide Gap PLZKBR7B8DG Platinum 26.5mm Reach Bi-Hex 14mm Gasket, Solid Extended Projection PZNAR6A11H · ZNAR6AGP Platinum 26.5mm Reach 14mm Hex Tapered, Solid Extended Projection Wide Gap LKAR6AHX · LKAR7AHX-S Ruthenium HX 26.5mm Reach 14mm Hex Gasket, Solid Projected, Wide Gap Dual Fine Electrode LKAR8BHX Ruthenium HX 26.mm Reach 14mm Hex Gasket, Solid Projected PSPE LKR6AHX · LKR7AHX-S Ruthenium HX 26.5mm Reach 5/8" Hex Gasket, Solid Projected, Wide Gap Dual Fine Electrode LKR6BHX-E · LKR7BHX · LKR8BHX-S Ruthenium HX 26.5mm Reach 5/8" Hex Gasket, Solid Projected PSPE [D6EA](/products/d6ea-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [D7EA](/products/d7ea-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [D8EA](/products/d8ea-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [D9EA](/products/d9ea-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [J9A](/products/j9a-ngk-standard-spark-plug-genuine-ngk-spark-plug) · J10A Standard, non-resistor 3/4" Reach 18mm Hex Gasket, Stud [D6HA](/products/d6ha-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [D8HA](/products/d8ha-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, non-resistor 1/2" Reach 18mm Hex Gasket, Stud DP6EA-9 · [DP7EA-9](/products/dp7ea-9-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [DP8EA-9](/products/dp8ea-9-ngk-standard-spark-plug-genuine-ngk-spark-plug) · DP9EA-9 Standard, non-resistor 3/4" Reach 18mm Hex Gasket, Stud Projected, Wide Gap [DCPR6E](/products/dcpr6e-ngk-spark-plug) · [DCPR8EKC](/products/dcpr8ekc-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [DCPR9E](/products/dcpr9e-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [KR9C-G](/products/kr9c-g-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid Projected 2-Ground Electrode [DCPR7E](/products/dcpr7e-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [DCPR8E](/products/dcpr8e-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Loose Projected [DCPR7E-N-10](/products/dcpr7e-n-10-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid Projected, Wide Gap [DPR5EA-9](/products/dpr5ea-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [DPR6EA-9](/products/dpr6ea-9-ngk-spark-plug-5531) · [DPR7EA-9](/products/dpr7ea-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [DPR8EA-9](/products/dpr8ea-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [DPR9EA-9](/products/dpr9ea-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 18mm Hex Gasket, Stud Projected, Wide Gap [DPR6EB-9](/products/dpr6eb-9-ngk-spark-plug) Standard, resistor 3/4" Reach 18mm Hex Gasket, Solid Projected, Wide Gap [DPR8Z](/products/dpr8z-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [DPR9Z](/products/dpr9z-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 18mm Hex Gasket, Stud Projected, Extended Shell DR4HS · [DR5HS](/products/dr5hs-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [DR6HS](/products/dr6hs-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · DR8HS Standard, resistor 1/2" Reach 18mm Hex Gasket, Stud [DR7EA](/products/dr7ea-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [DR7ES](/products/dr7es-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [DR8EA](/products/dr8ea-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [DR8ES](/products/dr8es-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [DR9EA](/products/dr9ea-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [JR9B](/products/jr9b-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · JR10B Standard, resistor 3/4" Reach 18mm Hex Gasket, Stud [DR7EB](/products/dr7eb-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · DR8EB Standard, resistor 3/4" Reach 18mm Hex Gasket, Solid [DR8ES-L](/products/dr8es-l-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 18mm Hex Gasket, Stud Half Heat Range Cooler JR8C · [JR9C](/products/jr9c-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 18mm Hex Gasket, Stud 2-Ground Electrode [KR9E-G](/products/kr9e-g-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid Projected LKAR8A-9 Standard, resistor 26.5mm Reach 14mm Hex Gasket, Solid Projected Wide Gap [LKR6E](/products/lkr6e-ngk-spark-plug) · [LKR7B-9](/products/lkr7b-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [LKR7E](/products/lkr7e-ngk-spark-plug) Standard, resistor 26.5mm Reach 5/8" Hex Gasket, Solid Projected [LKR8A](/products/lkr8a-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, resistor 26.5mm Reach 5/8" Hex Gasket, Solid Projected 2-Ground Electrode [LZKAR7A](/products/lzkar7a-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 26.5mm Reach 5/8" Hex Gasket, Solid Extended Projection ### 10mm Spark Plugs 140 plugs NGK plug Range Reach Hex Seat Notes CPR7EAIX-9 Iridium 3/4" Reach 5/8" Hex Gasket, Stud Projected, Wide Gap CR6EIA-9 · CR7EIA-9 · [CR8EIA-9](/products/cr8eia-9-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [CR8EIA-10](/products/cr8eia-10-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [CR9EIA-9](/products/cr9eia-9-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 3/4" Reach 5/8" Hex Gasket, Stud Wide Gap [CR6HIX](/products/cr6hix-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [CR7HIX](/products/cr7hix-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · CR8HIX Iridium 1/2" Reach 5/8" Hex Gasket, Stud CR7EIX · [CR8EIX](/products/cr8eix-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [CR9EIX](/products/cr9eix-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · CR10EIX Iridium 3/4" Reach 5/8" Hex Gasket, Loose CR8EHIX-9 · CR9EHI-9 · [CR9EHIX-9](/products/cr9ehix-9-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [IMR8C-9H](/products/imr8c-9h-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · IMR9A-9H · [IMR9C-9H](/products/imr9c-9h-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · IMR9C-9HE · [IMR9C-9HES](/products/imr9c-9hes-ngk-iridium-spark-plug-genuine-ngk-spark-plug) · [IMR9E-9HES](/products/imr9e-9hes-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 3/4" Reach 5/8" Hex Gasket, Stud Partial Thread, Wide Gap CR8EIB-9 · CR9EIB-9 · MR7BI-8 · MR8AI9 · MR8BI-8 Iridium 3/4" Reach 5/8" Hex Gasket, Solid [CR8EIB-10](/products/cr8eib-10-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 3/4" Reach 5/8" Hex Gasket, Solid Wide Gap DIMR8B10 · DIMR8C10 Iridium 3/4" Reach 5/8" Hex Gasket, Solid Projected, Wide Gap Dual Fine Electrode IMR8E-9HES Iridium 3/4" Reach 5/8" Hex Gasket, Solid Projected, Wide Gap IMR9B-9H · [IMR9D-9H](/products/imr9d-9h-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 3/4" Reach 5/8" Hex Gasket, Solid Partial Thread, Wide Gap LMAR7DI-10 Iridium 26.5mm Reach 14mm Hex Gasket, Stud Projected LMAR8AI-8 · LMAR8BI-9 · [LMAR9AI-8](/products/lmar9ai-8-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5 mm Reach 14 mm Hex Gasket, Solid [LMAR9AI-10](/products/lmar9ai-10-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5 mm Reach 14 mm Hex Gasket, Solid Wide Gap SILMAR7A9S · SILMAR8A9S · [SILMAR9A9S](/products/silmar9a9s-iridium-spark-plug) · SILMAR10A9S Iridium 26.5mm Reach 14mm Hex, SPE Gasket, Solid [SILMAR9B9](/products/silmar9b9-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 26.5mm Reach 5/8" Hex, SPE Gasket, Stud R0045J-9 · R0045J-11 NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid Surface Discharge Non-Resistor R0045Q-9 · R0045Q-10 · R0045Q-11 NGK Racing 3/4" Reach 5/8" Hex Gasket, Loose Surface Discharge Resistor R0373A-9 · R0373A-10 · R0373A-11 NGK Racing 3/4" Reach 5/8" Hex Gasket, Stud Fine Wire, Iridium Resistor R0406A-8 NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid Fine Wire, Iridium Resistor [R0409B-8](/products/r0409b-8-ngk-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing 3/4" Reach 5/8" Hex Gasket, Stud Fine Wire Resistor, Partial Thread R0451B-8 NGK Racing 26.5mm Reach 14mm Hex Gasket, Solid Fine Wire, Iridium Resistor CR8EKPA · CR9EKPA Platinum 3/4" Reach 5/8" Hex Gasket, Stud 2-Ground Electrode [PMR7A](/products/pmr7a-ngk-platinum-spark-plug-genuine-ngk-spark-plug) · [PMR8A](/products/pmr8a-ngk-platinum-spark-plug-genuine-ngk-spark-plug) · [PMR8B](/products/pmr8b-ngk-platinum-spark-plug-genuine-ngk-spark-plug) · PMR9A Platinum 3/4" Reach 5/8" Hex Gasket, Solid SPMR8A6HDG Platinum 22 mm Reach 5/8" Hex Gasket, Solid C2H · [C6HSA](/products/c6hsa-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [C7HSA](/products/c7hsa-ngk-standard-spark-plug-genuine-ngk-spark-plug) · C8HA · [C8HSA](/products/c8hsa-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, non-resistor 1/2" Reach 5/8" Hex Gasket, Stud C7E · [C8E](/products/c8e-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [C9E](/products/c9e-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, non-resistor 3/4" Reach 5/8" Hex Gasket, Stud C8EH-9 Standard, non-resistor 3/4" Reach 5/8" Hex Gasket, Stud Partial Thread, Wide Gap C-50 Standard, non-resistor 8.5mm Reach 13/16" Hex Gasket, Loose [CM-6](/products/cm-6-ngk-standard-compact-spark-plug-genuine-ngk-spark-plug) Standard, non-resistor 8.6mm Reach 5/8" Hex Gasket, Solid [CMR4A](/products/cmr4a-ngk-standard-compact-spark-plug-genuine-ngk-spark-plug) · [CMR6A](/products/cmr6a-ngk-standard-compact-spark-plug-genuine-ngk-spark-plug) · [CMR7A](/products/cmr7a-ngk-standard-compact-spark-plug-genuine-ngk-spark-plug) · CMR7A-5 Standard, resistor 3/8" Reach 5/8" Hex Gasket, Solid Compact CMR4H · [CMR5H](/products/cmr5h-ngk-standard-compact-spark-plug-genuine-ngk-spark-plug) · [CMR6H](/products/cmr6h-ngk-standard-compact-spark-plug-genuine-ngk-spark-plug) · [CMR7H](/products/cmr7h-ngk-standard-compact-spark-plug-genuine-ngk-spark-plug) · CMR8H Standard, resistor 1/2" Reach 5/8" Hex Gasket, Solid Compact CMR7H-10 Standard, resistor 1/2" Reach 5/8 Hex Gasket, Solid Compact Wide Gap [CPR6EA-9](/products/cpr6ea-9-spark-plug) · [CPR6EA-9S](/products/cpr6ea-9s-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CPR7EA-9](/products/cpr7ea-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CPR8EA-9](/products/cpr8ea-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CPR9EA-9](/products/cpr9ea-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Stud Projected, Wide Gap [CPR6EB-9](/products/cpr6eb-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CPR8EB-9](/products/cpr8eb-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · CPR9EB-9 Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid Projected, Wide Gap [CPR8E](/products/cpr8e-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [MR7F](/products/mr7f-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · MR8F · [MR9F](/products/mr9f-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid Projected CR4HSA · [CR5HSA](/products/cr5hsa-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · CR6HS · [CR6HSA](/products/cr6hsa-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · CR7HS · [CR7HSA](/products/cr7hsa-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR8HSA](/products/cr8hsa-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 1/2" Reach 5/8" Hex Gasket, Stud [CR4HSB](/products/cr4hsb-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR5HSB](/products/cr5hsb-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR6HSB](/products/cr6hsb-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · LR4C-E · [LR8B](/products/lr8b-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 1/2" Reach 5/8" Hex Gasket, Solid [CR5EH-9](/products/cr5eh-9-ngk-spark-plug) · [CR6EH-9](/products/cr6eh-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR7EH-9](/products/cr7eh-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR8EH-9](/products/cr8eh-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR9EH-9](/products/cr9eh-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Stud Partial Thread, Wide Gap [CR6E](/products/cr6e-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR7E](/products/cr7e-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR8E](/products/cr8e-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR9E](/products/cr9e-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR10E](/products/cr10e-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Stud [CR7EB](/products/cr7eb-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [CR8EB](/products/cr8eb-spark-plug-ngk) · [CR9EB](/products/cr9eb-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid [CR7EK](/products/cr7ek-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [CR8EK](/products/cr8ek-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [CR9EK](/products/cr9ek-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [CR10EK](/products/cr10ek-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Stud 2-Ground Electrode [CR7EKB](/products/cr7ekb-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [CR8EKB](/products/cr8ekb-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [CR9EKB](/products/cr9ekb-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid 2-Ground Electrode [CR7HSA-9](/products/cr7hsa-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 1/2" Reach 5/8" Hex Gasket, Stud Wide Gap [LMAR6A-9](/products/lmar6a-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [LMAR7A-9](/products/lmar7a-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · [LMAR8A-9](/products/lmar8a-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) · LMAR8A-9S Standard, resistor 26.5mm Reach 14mm Hex Gasket, Stud Projected [LMAR6C-9](/products/lmar6c-9-ngk-spark-plug) · LMAR8C-9 Standard, resistor 26.5mm Reach 14mm Hex Gasket, Solid Projected [LMAR8D-J](/products/lmar8d-j-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [LMAR9D-J](/products/lmar9d-j-ngk-multiground-spark-plug-genuine-ngk-spark-plug) Standard, resistor 26.5mm Reach 14mm Hex Gasket, Solid 2-Ground Electrode [LMAR8F-9](/products/lmar8f-9-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor 26.5 mm Reach 14 mm Hex Gasket, Solid [LMAR9E-J](/products/lmar9e-j-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, resistor 26.5mm Reach 14mm Hex Gasket Projected 2-Ground Electrode MAR8B-JDS Standard, resistor 3/4" Reach 14 mm Hex Partial Thread [MAR9A-J](/products/mar9a-j-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [MAR10A-J](/products/mar10a-j-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, resistor 3/4" Reach 14mm Hex Gasket, Solid 2-Ground Electrode ### 18mm Spark Plugs 12 plugs NGK plug Range Reach Hex Seat Notes WR5IX Iridium .460" Reach 13/16" Hex Tapered, Solid Projected R8102A-10 NGK Racing 16mm Reach 25.4mm Hex Gasket, Loose Non-Resistor [A6FS](/products/a6fs-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, non-resistor .460" Reach 13/16" Hex Tapered, Solid [AB-2](/products/ab-2-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [AB-6](/products/ab-6-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [AB-7](/products/ab-7-ngk-standard-spark-plug-genuine-ngk-spark-plug) · AB-8 Standard, non-resistor 12mm Reach 13/16" Hex Gasket, Loose [AP7FS](/products/ap7fs-ngk-standard-spark-plug-genuine-ngk-spark-plug) · [AP8FS](/products/ap8fs-ngk-standard-spark-plug-genuine-ngk-spark-plug) Standard, non-resistor .460" Reach 13/16" Hex Tapered, Solid Projected [AR6FS](/products/ar6fs-ngk-standard-resistor-spark-plug-genuine-ngk-spark-plug) Standard, resistor .460" Reach 13/16" Hex Tapered, Solid WR4-1 V-Power .460" Reach 13/16" Hex Tapered, Solid Extended Projection WR5 V-Power .460" Reach 13/16" Hex Tapered, Solid Projected ### 8mm Spark Plugs 3 plugs NGK plug Range Reach Hex Seat Notes ER8EHIX · [ER9EHIX](/products/er9ehix-ngk-iridium-spark-plug-genuine-ngk-spark-plug) Iridium 3/4" Reach 13mm Hex Gasket, Stud ER9EH Standard, resistor 3/4" Reach 13mm Hex Gasket, Stud ### Racing Spark Plugs 79 plugs NGK plug Range Reach Hex Seat Notes [B8EG](/products/b8eg-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [B9EG](/products/b9eg-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [B10EG](/products/b10eg-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · B11EG NGK Racing 3/4" Reach 13/16" Hex Gasket, Loose Fine Wire Non-Resistor B8EG SOLID · B9EG SOLID NGK Racing 3/4" Reach 13/16" Hex Gasket, Solid Fine Wire Non-Resistor B10EGP · B10EGV · R4118S-8 NGK Racing 3/4" Reach 13/16" Hex Gasket, Loose Gold Palladium Non-Resistor [BR8EG](/products/br8eg-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [BR9EG](/products/br9eg-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing 3/4" Reach 13/16" Hex Fine Wire BR8EG SOLID · BR9EG SOLID · [BR9EG-N-8](/products/br9eg-n-8-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · BR10EG SOLID NGK Racing 3/4" Reach 13/16" Hex Gasket, Solid Fine Wire Resistor R5184-105 NGK Racing 3/4" Reach 13/16" Hex Gasket, Loose Gold Palladium Low Angle Ground Electrode Non-Resistor [R5671A-7](/products/r5671a-7-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5671A-8](/products/r5671a-8-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5671A-9](/products/r5671a-9-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5671A-10](/products/r5671a-10-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5671A-11](/products/r5671a-11-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid V-Power Non-Resistor [R5672A-8](/products/r5672a-8-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5672A-9](/products/r5672a-9-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5672A-10](/products/r5672a-10-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid V-Power, Projected Non-Resistor [R5673-9](/products/r5673-9-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5673-10](/products/r5673-10-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing .460" Reach 5/8" Hex Tapered, Solid V-Power Non-Resistor R5674-6 · [R5674-7](/products/r5674-7-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5674-8](/products/r5674-8-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5674-9](/products/r5674-9-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · R5674-10 NGK Racing .460" Reach 5/8" Hex Tapered, Solid V-Power Projected Non-Resistor [R5724-8](/products/r5724-8-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5724-9](/products/r5724-9-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) · [R5724-10](/products/r5724-10-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing .708" Reach 5/8" Hex Tapered, Solid Projected Non-Resistor R6021E-9 NGK Racing 3/4" Reach 13/16" Hex Gasket, Loose Fine Wire R6061-8 · [R6061-9](/products/r6061-9-ngk-racing-spark-plug-genuine-ngk-spark-plug) · R6061-10 · R6061-11 · R6254E-9 · R6254E-105 · [R6254K-105](/products/r6254k-105-ngk-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing 3/4" Reach 13/16" Hex Gasket, Solid Low Angle Ground Electrode Non-Resistor R6252E-105 · [R6252K-105](/products/r6252k-105-ngk-standard-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing 3/4" Reach 13/16" Hex Gasket, Solid Low Angle Ground Electrode Resistor R6601-10 · [R6601-11](/products/r6601-11-ngk-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid Semi-Surface Dis- charge Resistor R6711-9 · R6711-10 NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid Semi-Surface Dis- charge Non-Resistor R6712-9 NGK Racing 3/4" Reach 13/16" Hex Gasket, Loose Surface Discharge Resistor R6725-11 · R6725-105 · [R6725-115](/products/r6725-115-ngk-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing 21.5mm Reach 13/16" Hex Gasket, Solid Platinum Low Angle Ground Electrode Resistor [R6918B-7](/products/r6918b-7-ngk-cold-range-racing-spark-plug-genuine-ngk-spark-plug) · R6918B-8 · R6918B-9 · R6918C-9 NGK Racing 3/4" Reach 13/16" Hex Gasket, Solid Platinum Low Angle Ground Electrode Resistor R7282-10 · R7282-11 · R7282-105 NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid Iridium, Short Resistor R7282A-10 NGK Racing 22mm Reach 5/8" Hex Gasket, Solid Iridium Low Angle Ground Electrode Short Resistor R7376-8 · R7376-9 · R7376-10 NGK Racing 3/4" Reach 13/16" Hex Gasket, Solid Iridium Low Angle Ground Electrode Resistor R7420-9 · R7420-10 · R7420-11 · [R7420-105](/products/r7420-105-ngk-racing-spark-plug-genuine-ngk-spark-plug) · R7440A-10L NGK Racing 21mm Reach 13/16" Hex Gasket, Solid Iridium Low Angle Ground Electrode Resistor R7433-8 · R7433-9 NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid Iridium ISO, Projected Resistor R7434-10 NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid Iridium ISO, Low Angle Ground Electrode Resistor [R7435-9](/products/r7435-9-ngk-racing-spark-plug-genuine-ngk-spark-plug) NGK Racing 3/4" Reach 5/8" Hex Iridium, JIS, Projected R7435-10 NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid Iridium, JIS, Projected Resistor R7436-9 · R7436-10 NGK Racing 3/4" Reach 5/8" Hex Gasket, Solid Iridium JIS, Low Angle Ground Electrode Resistor R7437-8 · R7437-9 NGK Racing 26.5mm Reach 5/8" Hex Gasket, Solid Iridium Projected Resistor R7438-8 · R7438-9 NGK Racing 26.5mm Reach 5/8" Hex Gasket, Solid Iridium Low Angle Ground Electrode Resistor ### PF1/2S Spark Plugs 1 plug NGK plug Range Reach Hex Seat Notes G-2Z Standard, non-resistor 22.5mm Reach 23.8mm Hex Gasket, Stud ### Thread size not listed 9 plugs NGK plug Range Reach Hex Seat Notes FR5BHX Ruthenium HX 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected Wide Gap PSPE LFER7BHX · LFR6AHX-S · LFR6BHX Ruthenium HX 26.5mm Reach 5/8" Hex Gasket, Solid Projected, Wide Gap Dual Fine Electrode 26.5mmReach Projected PSPE LFR5AHX Ruthenium HX 2.6mm Reach 5/8" Hex Gasket, Solid Projected Dual Fine Electrode LTR5AHX Ruthenium HX 25mm Reach 5/8" Hex Tapered, Solid Projected Dual Fine Electrode LTR6AHX Ruthenium HX 25mm Reach 5/8" Hex Tapered, Solid Projected, Wide Gap Dual Fine Electrode LTR6BHX · LTR7BHX Ruthenium HX 25mm Reach 5/8" Hex Tapered, Solid Projected PSPE ### Reading the specification **Reach** is the threaded length that screws into the head. **Hex** is the spanner size — 5/8" and 13/16" are the two common plug sockets. **Seat** is how the plug seals: a gasket seat uses a captive washer, a tapered seat seals on the cone and takes no washer. _Solid_ and _loose_ describe the gasket, and _stud_ means the terminal nut screws off so the plug takes either a threaded or a push-on cap. **Projected** means the insulator nose reaches further into the chamber, which suits engines designed for it and can foul or contact in engines that are not. **Wide gap** plugs come pre-gapped wider for high-energy ignition systems. Fit what the engine manufacturer specifies rather than substituting on dimensions alone. ### Other reference tables - [14mm Plugs](/pages/ngk-spark-plug-specifications) - [Denso cross reference](/pages/ngk-cross-reference-denso) - [Champion cross reference](/pages/ngk-cross-reference-champion) - [Bosch cross reference](/pages/ngk-cross-reference-bosch) - [Autolite & Motorcraft cross reference](/pages/ngk-cross-reference-autolite-motorcraft) - [ACDelco & Torch cross reference](/pages/ngk-cross-reference-acdelco) - [Other brands & OEM cross reference](/pages/ngk-cross-reference-other-brands) - [All reference charts](/pages/resources) --- > Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/pages/ngk-spark-plug-specifications-small-thread)