NGK Spark Plug Dimensions: 14mm Plugs

NGK Spark Plug Dimensions: 14mm Plugs

683 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.

14mm Spark Plugs 683 plugs

NGK plug Range Reach Hex Seat Notes
BCPR5EIX · BCPR6EIX · BCPR7EIX Iridium 3/4" Reach 5/8" Hex Gasket, Solid JIS Projected
BCPR5EIX-11 · BCPR6EIX-11 · BCPR7EIX-11 Iridium 3/4" Reach 5/8" Hex Gasket, Solid JIS Projected Wide Gap
BKR4EIX · BKR5EIX · BKR6EIX · BKR7EIX · BKR8EIX · BKR9EIX Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected BK-Series
BKR5EIX-11 · BKR6EIX-11 · BKR7EIX-11 Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected BK-Series Wide Gap
BPR5EIX · BPR6EIX · BPR7EIX · BPR8EIX · BPR9EIX · BPR10EIX Iridium 3/4" Reach 13/16" Hex Gasket, Loose Projected
BPR5EIX-11 · BPR6EIX-11 Iridium 3/4" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap
BPR6HIX · BPR7HIX · BPR8HIX Iridium 1/2" Reach 13/16" Hex Gasket, Loose Projected
BR6FIX · YR5IX Iridium .460" Reach 5/8" Hex Tapered, Solid
BR6HIX · BR7HIX · BR8HIX · BR9HIX · BR10HIX Iridium 1/2" Reach 13/16" Hex Gasket, Loose
BR7EIX · BR8EIX · BR9EIX · BR10EIX Iridium 3/4" Reach 13/16" Hex Gasket, Loose
BR8ECMIX · BR9ECMIX · BR10ECMIX Iridium 3/4" Reach 13/16" Hex Gasket, Solid Compact
BR8ECSIX · BR9ECSIX Iridium 3/4" Reach 13/16" Hex Gasket, Solid Low Angle
BR8EIX SOLID · BR9EIX SOLID · BR10EIX SOLID · IGR7A-G Iridium 3/4" Reach 13/16" Hex Gasket, Solid
BR9ECSIX-5 Iridium 3/4" Reach 13/16" Hex Gasket, Solid Low Angle, Narrow Gap
DFH6B-11A · DILFR5A11 · DILFR5A11D · DILFR5C11D · DILFR6D11 · DILFR6J11 · DILFR7B10G · DILFR7K9G Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Projected, Wide Gap Dual Fine Electrode
DIFR5C11 · DIFR6C11 · DIFR6D13 Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected Dual Fine Electrode Wide Gap
FR5EI · FR6EI · IFR5T-8N · IFR6B · IFR6B-K · IFR6Q-G · IFR7F-4D · IFR7F-8DS · IFR7X7G Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series
FR9BI-11 · IFR5D10 · IFR5E11 · IFR5G11 · IFR5G-11K · IFR5J11 · IFR5L11 · IFR5N10 · IFR5T11 · IFR6B11 Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series Wide Gap
GR4IX · GR5IX Iridium 3/4" Reach 13/16" Hex Gasket, Solid Projected
IFR6D10 · IFR6E11 · IFR6G-11K · IFR6J11 · IFR6L11 · IFR6T11 · IFR6V-10G · IFR7G-11KS · IFR7L11 · IFR8H11 Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series Wide Gap
IFR9H11 Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series Wide Gap
ILFR5B11 · ILFR5T11 · ILFR6J-11K · ILFR6T11 · LFR5AIX-11 · LFR6AIX-11 · SILFR6A11 Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Projected, Wide Gap
ILFR6A · ILFR6B · ILFR6G-E · ILFR7H · LFR6AIX · LFR7AIX · SILFR6A Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Projected
ILTR5B11 · ILTR5C11 · ILTR5E11 · ILTR5K13 · ILTR5L11 · ILTR6B11 · ILTR6E11 · LTR5BI-13 · LTR5IX-11 · LTR6AI13 Iridium 25mm Reach 5/8" Hex Tapered, Solid Projected, Wide Gap
ILTR5D · ILTR5M9G · ILTR6A-8G · ILTR6F9 · ILTR6G8G · ILTR6M9G · ILTR7E9 · ILTR7N8 · LTR6BI-9 · LTR6CI-8 Iridium 25mm Reach 5/8" Hex Tapered, Solid Projected
ILTR6H8G Iridium 25mm Reach 5/8" Hex Tapered, Loose Projected
ILZFR6D11 · LZFR5AIX-11E · LZFR5BI-11 · LZFR5CI-11 Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Wide Gap Extended Projection
ILZTR6A8G Iridium 25mm Reach 5/8" Hex Tapered, Solid Extend Shell Extended Projection
ITR4A15 · ITR5H13 · ITR6F13 · TR5AI-13 · TR55IX · TR65IX Iridium .708" Reach 5/8" Hex Tapered, Solid Projected, Wide Gap
IZFR5B · IZFR5G · IZFR5J · IZFR6J · IZFR6N-E · IZFR6Q · IZFR7M · ZFR5FIX-E Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Extended Projection
IZFR5K11 · IZFR5L11 · IZFR6F11 · IZFR6H11 · IZFR6K11 · IZFR6K13 · IZFR6K-11E · IZFR6K-11S · ZFR5AIX-11 · ZFR5FIX-11 Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Extended Projection Wide Gap
IZTR4A11 · IZTR5B11 Iridium .708" Reach 5/8" Hex Tapered, Solid Extended Projection Wide Gap
LTR6BI-13 · LTR6IX-11 · LTR7IX-11 Iridium 25mm Reach 5/8" Hex Tapered, Solid Projected, Wide Gap
LTR6DI-8 · LTR6IX · LTR61X · SILTR6A7G Iridium 25mm Reach 5/8" Hex Tapered, Solid Projected
LZFR6AI Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Extended Projection
LZTR4AIX-11 · LZTR5AIX-13 · LZTR6AIX-13 · LZTR7AIX-13 Iridium 25mm Reach 5/8" Hex Tapered, Solid Extended Projection Wide Gap
RE7C-L Iridium 21mm Reach 13/16" Hex Gasket, Solid Slant/Slit
RE9B-T Iridium 19mm Reach 13/16" Hex Gasket, Solid Slant/Slit
SIFR6A11 Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected PSPE Wide Gap
SILFR5A11 · SILFR6C11 Iridium 26.5mm Reach 5/8" Hex Gasket, Solid, PSPE Projected, Wide Gap
SILFR6B8 Iridium 26.5mm Reach 5/8" Hex Gasket, Solid Projected, PSPE
TR4IX · TR5IX · TR6IX · TR7IX · TR8IX Iridium .708" Reach 5/8" Hex Tapered, Solid Projected
TR5-1IX Iridium .708" Reach 5/8" Hex Tapered, Solid Projected Extended Shell
TR45-1IX · TR55-1IX Iridium .708" Reach 5/8" Hex Tapered, Solid Projected Extended Shell Wide Gap
UR4IX · UR5IX · UR6IX Iridium .460" Reach 5/8" Hex Tapered, Solid Projected
UR45IX · UR55IX Iridium .460" Reach 5/8" Hex Tapered, Solid Projected, Wide Gap
XR4IX · XR5IX Iridium 3/8" Reach 13/16" Hex Gasket, Solid Projected
XR45IX Iridium 3/8" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap
YR55IX Iridium .460" Reach 5/8" Hex Tapered, Solid Wide Gap
ZFR5FIX-11E · ZFR6AIX-11S · ZFR6FIX-11 Iridium 3/4" Reach 5/8" Hex Gasket, Solid ISO Extended Projection Wide Gap
R5670-5 · R5670-6 · R5670-7 · R5670-8 · R5670-9 NGK Racing 3/8" Reach 13/16" Hex Gasket, Solid Projected V-Power Non-Resistor
R5673-6 · R5673-7 · R5673-8 NGK Racing .460" Reach 5/8" Hex V-Power
BCPR5EGP · BCPR5EP-8 · BCPR6EGP Platinum 3/4" Reach 5/8" Hex Gasket, Solid JIS Projected
BCPR5EP-11 · BCPR6EP-11 · BCPR6EP-N-8 · BCPR6EP-N-11 · PFR5A-11 · PFR6A-11 · PFR6H-10 · PFR7H-10 Platinum 3/4" Reach 5/8" Hex Gasket, Solid JIS Projected Wide Gap
BKR5EGP · BKR6EGP · BKR6EP-8 Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected BK-Series
BKR5EKPB-11 · BKR6EKPB-11 Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected 2-Ground Electrode Wide gap
BKR5EKUP Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected Semi-Surface Discharge
BKR5EP-11 · BKR6EP-11 Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected BK-Series Wide Gap
BKR6EQUP · BKR7EQUP Platinum 3/4" Reach 5/8" Hex Gasket, Solid 4-Ground Electrode
BPR5EGP · BPR6EGP Platinum 3/4" Reach 13/16" Hex Gasket, Loose Projected
BPR5EP-11 · GR45GP · PGR5A-11 · PGR5C-11 Platinum 3/4" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap
BUR7EQP · BUR9EQP Platinum 21.5 mm Reach 13/16" Hex Gasket, Solid 4-Ground Electrode
FR4GP · FR5GP · PFR6B · PFR6G · PFR6Q · PFR7AB · PFR7B · PFR7N8DS · PFR7Q · PFR7S8EG Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series
FR5AP-10 · FR5AP-11 · FR5AP-11E · FR45GP · PFR5B-11 · PFR5B-11B · PFR5C-11 · PFR5G-11 · PFR5G-13E · PFR5J-11 Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series Wide Gap
GR4GP · GR5GP · PGR6A · PGR7A Platinum 3/4" Reach 13/16" Hex Gasket, Solid Projected
ITR6G9 Platinum .708" Reach 5/8" Hex Tapered, Loose
LFR6CGP · PLFR6A-11 · PLFR6C-10G Platinum 26.5mm Reach 5/8" Hex Gasket, Solid Projected, Wide Gap
LTR5GP · LTR6GP-8 Platinum 25mm Reach 5/8" Hex Tapered, Solid Projected
LTR6BP13 · LTR6DP13 · LTR6GP · LTR7CP13 · PLTR6A-10G · PTR5A-13 Platinum 25mm Reach 5/8" Hex Tapered, Solid Projected, Wide Gap
LZFR5AGP-E · LZFR6AP116S · PLZFR5B13EG · PLZFR6A-11S Platinum 26.5mm Reach 5/8" Hex Gasket, Solid Wide Gap Extended Projection
LZTR4AGP · LZTR5AGP · LZTR6AP11EG · PLZTR4A-13 · PLZTR5A-13 Platinum 25mm Reach 5/8" Hex Tapered, Solid Extended Projection Wide Gap
PFR5L-11 · PFR5N-11 · PFR5R-11 · PFR6B-11 · PFR6G-11 · PFR6G-13 · PFR6G-13E · PFR6J-11 · PFR6L-11 · PFR6L-13 Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series Wide Gap
PFR6N-11 · PFR6T-10G · PFR6U-11G · PFR6X-11 · PFR7G-11 · PFR7G-11S Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series Wide Gap
PFR6W-TG · PFR7W-TG Platinum 3/4" Reach 5/8" Hex Gasket, Solid 3-Ground Electrode
PFR8S8EG Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series
PLFER7A8EG Platinum 26.5mm Reach 5/8" Hex Gasket, Solid Projected
PLFR5A-11 Platinum 26.5mm Reach 5/8" Hex Gasket, Solid, PSPE Projected, Wide Gap
PTR4B-15 · PTR4G-15 · PTR5C-13 · PTR5D-13 · PTR5F-11 · PTR6D-13 · TR5BP12 · TR6AP-13 · TR6AP-13E · TR55GP Platinum .708" Reach 5/8" Hex Tapered, Solid Projected, Wide Gap
PTR5D-10 · TR4GP · TR5GP · TR6GP Platinum .708" Reach 5/8" Hex Tapered, Solid Projected
PZFR5D-11 · PZFR5F-11 · PZFR5J-11 · PZFR5Q-11 · PZFR6E-11 · PZFR6F-11 · PZFR6J-11 · ZFR5LP-13G · ZFR6AGP Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Extended Projection Wide Gap
PZFR5F · PZFR6F · PZFR6H · PZFR7G-G · ZFR5AP · ZFR5BGP · ZFR5EGP · ZFR5FGP · ZFR5FGP-8E · ZFR5FGP-E Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Extended Projection
PZTR5A-15 Platinum .708" Reach 5/8" Hex Tapered, Solid Extended Projection Wide Gap
TR5-1GP Platinum .708" Reach 5/8" Hex Tapered, Solid Projected Extended Shell
TR45-1GP · TR55-1GP Platinum .708" Reach 5/8" Hex Tapered, Solid Projected Extended Shell Wide Gap
UR4GP · UR5GP · UR6GP Platinum .460" Reach 5/8" Hex Tapered, Solid Projected
UR45GP Platinum .460" Reach 5/8" Hex Tapered, Solid Projected, Wide Gap
YR5GP Platinum .460" Reach 5/8" Hex Tapered, Solid
ZFR6BGP-S · ZFR6FGP Platinum 3/4" Reach 5/8" Hex Gasket, Solid ISO Extended Projection
ZGR5AGP Platinum 3/4" Reach 13/16" Hex Gasket, Solid Extended Projection
FR5AHX · FR6AHX-S Ruthenium HX 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected Wide Gap Dual Fine Electrode
FR5AHX-E Ruthenium HX 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected Dual Fine Electrode
FR6BHX-S · FR7BHX-S Ruthenium HX 3/4" Reach 5/8 Hex Gasket, Solid ISO Projected PSPE
TR4BHX Ruthenium HX .708" Reach 5/8" Hex Tapered, Solid Projected PSPE
TR5AHX · TR6AHX Ruthenium HX .708" Reach 5/8" Hex Tapered, Solid Projected Wide Gap Dual Fine Electrode
B2-LM · B4-LM Standard, non-resistor 3/8" Reach 13/16" Hex Gasket, Loose Compact
B4-L · B6-L Standard, non-resistor 7/16" Reach 13/16" Hex Gasket, Loose
B4ES · B5ES · B6ES · B7ES · B8ES · B9ES · B10ES Standard, non-resistor 3/4" Reach 13/16" Hex Gasket, Loose
B4H · B5HS · B6HS · B7HS · B8HS · B9HS · B10HS Standard, non-resistor 1/2" Reach 13/16" Hex Gasket, Loose
B6ES-11 · B7ES-11 Standard, non-resistor 3/4" Reach 13/16" Hex Gasket, Solid Wide Gap
B6HS-10 · B7HS-10 · B8HS-10 · B9HS-10 Standard, non-resistor 1/2" Reach 13/16" Hex Gasket, Loose Wide Gap
B6S · B7S · B8S · B-2 · B-4 Standard, non-resistor 3/8" Reach 13/16" Hex Gasket, Loose
B7ES SOLID · B8ES SOLID · B9ES SOLID Standard, non-resistor 3/4" Reach 13/16" Hex Gasket, Solid
B8EFS · B9EFS Standard, non-resistor .708" Reach 5/8" Hex Tapered, Loose
BCP4ES-11 · BCP6ES-11 Standard, non-resistor 3/4" Reach 5/8" Hex Gasket, Solid JIS Projected Wide Gap
BCP5ES · BCP6ES · BCP7ES Standard, non-resistor 3/4" Reach 5/8" Hex Gasket, Solid JIS Projected
BCP6ET Standard, non-resistor 3/4" Reach 5/8" Hex Gasket, Loose 3-Ground Electrode JIS Projected
BM4A · BM6A · BM7A Standard, non-resistor 3/8" Reach 3/4" Hex Gasket, Loose Compact
BM4A SOLID · BM6A SOLID Standard, non-resistor 3/8" Reach 3/4" Hex Gasket, Solid Compact
BM6F · BM7F Standard, non-resistor 3/8" Reach 5/8" Hex Tapered, Loose Compact
BP4ES · BP5ES · BP6ES · BP7ES · BP8ES · BP9ES Standard, non-resistor 3/4" Reach 13/16" Hex Gasket, Loose Projected
BP4HS · BP5HS · BP6HS · BP7HS · BP8HS Standard, non-resistor 1/2" Reach 13/16" Hex Gasket, Loose Projected
BP4HS-10 · BP6HS-10 · BP7HS-10 · BP8HS-10 Standard, non-resistor 1/2" Reach 13/16" Hex Gasket, Loose Projected, Wide Gap
BP5EA-L · BP5ES SOLID · BP6ES SOLID · BP7ES SOLID · BP8ES SOLID Standard, non-resistor 3/4" Reach 13/16" Hex Gasket, Solid Projected
BP5ES-11 · BP6ES-11 Standard, non-resistor 3/4" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap
BP6ET Standard, non-resistor 3/4" Reach 13/16" Hex Gasket, Loose 3-Ground Electrode Projected
BP7EFS Standard, non-resistor .708" Reach 5/8" Hex Tapered, Loose Projected
BP8HS-15 Standard, non-resistor 1/2" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap
BPM4A · BPM6A · BPM7A Standard, non-resistor 3/8" Reach 3/4" Hex Gasket, Loose Compact, Projected
BPM6A-10 Standard, non-resistor 3/8" Reach 3/4" Hex Gasket, Solid Compact, Projected Wide Gap
BPM6F Standard, non-resistor 3/8" Reach 5/8" Hex Tapered, Solid Compact, Projected
BPM7A SOLID Standard, non-resistor 3/8" Reach 3/4" Hex Gasket, Solid Compact, Projected
BU8H · BUH · BUHX Standard, non-resistor 1/2" Reach 13/16" Hex Gasket, Solid Surface Discharge
BUE Standard, non-resistor 3/4" Reach 13/16" Hex Gasket, Solid Surface Discharge
BUHW · BUHW-2 · BUHXW-1 Standard, non-resistor 1/2" Reach 13/16" Hex Gasket, Solid Tungsten Electrode
BCPR5ES · BCPR6ES · BCPR7ES Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid JIS Projected
BCPR5ES-11 · BCPR6ES-11 · BCPR7ES-11 Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid JIS Projected Wide Gap
BCPR7ET Standard, resistor 3/4" Reach 5/8" Hex Gasket, Loose 3-Ground Electrode JIS Projected
BKR4ESA-11 · BKR5ES-11 · BKR5ESA-11 · BKR6ES-11 · BKR7ES-11 Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected BK-Series Wide Gap
BKR5EK · BKR6EK · BKR6EKC · BKR7EKC-N Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected 2-Ground Electrode
BKR5EKB-11 Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected 2-Ground Electrode Wide gap
BKR5EKU · BKR6EKU · BKR6EKUB · BKR6EKUE · BKR7EKU Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected Semi-Surface Discharge
BKR5ES · BKR6ES Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected BK-Series
BKR6EKE Standard, resistor 3/4" Reach 5/8" Hex Gasket, Loose ISO Projected 2-Ground Electrode
BKR6EQUA Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid 4-Ground Electrode
BKUR6ET · BKUR6ET-10 · BKUR6ETB · BKUR7ET Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid 3-Ground Electrode
BMR2A · BMR4A · BMR6A · BMR7A Standard, resistor 3/8" Reach 3/4" Hex Gasket, Loose Compact
BMR2A SOLID · BMR4A SOLID · BMR6A SOLID Standard, resistor 3/8" Reach 3/4" Hex Gasket, Solid Compact
BMR2A-10 Standard, resistor 3/8" Reach 3/4" Hex Gasket, Loose Compact, Wide Gap
BPMR4A SOLID · BPMR7A SOLID Standard, resistor 3/8" Reach 3/4" Hex Gasket, Solid Compact, Projected
BPMR4A-10 · BPMR6A-10 Standard, resistor 3/8" Reach 3/4" Hex Gasket, Solid Compact, Projected Wide Gap
BPMR6A · BPMR7A Standard, resistor 3/8" Reach 3/4" Hex Gasket, Loose Compact, Projected
BPMR6F Standard, resistor 3/8" Reach 5/8" Hex Tapered, Loose Compact, Projected
BPR2ES · BPR4ES · BPR5ES · BPR6ES · BPR7ES · BPR8ES Standard, resistor 3/4" Reach 13/16" Hex Gasket, Loose Projected
BPR2ES SOLID · BPR4ES SOLID · BPR5ES SOLID · BPR6ES SOLID · BPR7ES SOLID · BPR9ES · GR9A-EG Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid Projected
BPR4ES-11 · BPR5ES-11 · BPR6ES-11 · BPR7ES-11 Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap
BPR4ES-H Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid Extended Thread Shell Projected
BPR4HS · BPR5HS · BPR6HS · BPR7HS · BPR8HS Standard, resistor 1/2" Reach 13/16" Hex Gasket, Loose Projected
BPR4HS-10 · BPR6HS-10 · BPR7HS-10 Standard, resistor 1/2" Reach 13/16" Hex Gasket, Loose Projected, Wide Gap
BPR5EFS-13 · TR5C-12 Standard, resistor .708" Reach 5/8" Hex Tapered, Solid Projected, Wide Gap
BPR5EKU Standard, resistor 3/4" Reach 13/16" Hex Gasket, Loose Projected 2-Ground Electrode
BPR6EFS Standard, resistor .708" Reach 5/8" Hex Tapered, Solid Projected
BPR6EKN Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid Projected 2-Ground Electrode
BPR6FS Standard, resistor .460" Reach 5/8" Hex Tapered, Solid Projected
BPR6HSA Standard, resistor 1/2" Reach 13/16" Hex Gasket, Stud Projected
BPZ8HS-10 · BPZ8HS-15 Standard, resistor 1/2" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap Inductive Resistor
BR2-LM · BR4-LM Standard, resistor 3/8" Reach 13/16" Hex Gasket, Loose Compact
BR2-LM SOLID Standard, resistor 3/8" Reach 13/16" Hex Gasket, Solid Compact
BR4ES · BR5ES · BR6ES · BR7ES · BR8ES · BR9ES · BR10ES Standard, resistor 3/4" Reach 13/16" Hex Gasket, Loose
BR4HS · BR5HS · BR6HS · BR7HS · BR8HS · BR9HS Standard, resistor 1/2" Reach 13/16" Hex Gasket, Loose
BR6ES-11 · BR8ES-11 Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid Wide Gap
BR6FS Standard, resistor .460" Reach 5/8" Hex Tapered, Solid
BR6HS-10 · BR7HS-10 · BR8HS-10 · BR9HS-10 Standard, resistor 1/2" Reach 13/16" Hex Gasket, Loose Wide Gap
BR6HSA · BR8HSA Standard, resistor 1/2" Reach 13/16" Hex Gasket, Stud
BR6S Standard, resistor 3/8" Reach 13/16" Hex Gasket, Loose
BR7EFS Standard, resistor .708" Reach 5/8" Hex Tapered, Solid
BR7ES SOLID · BR8ES SOLID · BR9ES SOLID · BR10ES SOLID Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid
BR7ET · BR8ET · BR9ET Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid 3-Ground Electrode
BR8ECM · BR9ECM · BR10ECM Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid Compact
BR8ECS · BR9ECS · BR10ECS SOLID Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid Low Angle
BR8EQ-14 · BR9EQ-14 Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid 4-Ground Electrode Wide Gap
BR8HCS-10 Standard, resistor 1/2" Reach 13/16" Hex Gasket, Loose Low Angle Ground Electrode Wide Gap
BR8HS SOLID Standard, resistor 1/2" Reach 13/16" Hex Gasket, Solid
BR9ECS-5 Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid Low Angle, Narrow Gap
BUR4EB-11 · BUR5EB-11 · BUR6EB-11 · BUR7EB-11 Standard, resistor 3/4" Reach 13/16" Hex Gasket, Solid Semi-Surface Discharge Wide Gap
BUR6ET Standard, resistor 3/4" Reach 13/16" Hex Gasket, Loose 3-Ground Electrode Projected
BUR7EQ · BUR9EQ Standard, resistor 21.5 mm Reach 13/16" Hex Gasket, Solid 4-Ground Electrode
BUZ8H Standard, resistor 1/2" Reach 13/16" Hex Gasket, Solid Surface Discharge Inductive Resistor
BUZHW · BUZHW-2 Standard, resistor 1/2" Reach 13/16" Hex Gasket, Solid Tungsten Electrode Inductive Resistor
BZ7HS-10 Standard, resistor 1/2" Reach 13/16" Hex Gasket, Solid Inductive Resistor, Wide Gap
FR2B-D Standard, resistor 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected Partial Thread FR - Series
LFR6D Standard, resistor 26.5mm Reach 5/8" Hex Gasket, Solid 3-Ground Electrode
LZFR5C-11 Standard, resistor 26.5mm Reach 5/8" Hex Gasket, Solid Wide Gap Extended Projection
ZGR5A Standard, resistor 3/4" Reach 13/16" Hex Gasket, Loose Extended Projection
B2LMY BL1 · B4LMY BL1 V-Power 3/8" Reach 13/16" Hex Gasket, Loose Compact
B6LY BL1 V-Power 7/16" Reach 13/16" Hex Gasket, Loose
BCPR5E-11 · BCPR5EY-11 · BCPR6E-11 · BCPR6EY-11 · BCPR6EY-N-11 · BCPR7EY-11 V-Power 3/4" Reach 5/8" Hex Gasket, Solid JIS Projected Wide Gap
BCPR5EY · BCPR6E V-Power 3/4" Reach 5/8" Hex Gasket, Solid JIS Projected
BKR4E · BKR5E · BKR5EY · BKR5EYA · BKR6E · BKR6EY · BKR6EYA · BKR6EZB · BKR7E · BKR7E-E V-Power 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected BK-Series
BKR4E-11 · BKR5E-11 · BKR5E-N-11 · BKR5EY-11 · BKR5EYA-11 · BKR6E-11 · BKR6E-N-11 · BKR7E-11 V-Power 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected BK-Series Wide Gap
BM4Y BL1 · BM6Y BL1 · BM7Y BL1 V-Power 3/8" Reach 3/4" Hex Gasket, Loose Compact
BM6FY BL1 V-Power 3/8" Reach 5/8" Hex Tapered, Loose Compact
BP5EY · BPR5EY BL1 · BPR6EY BL1 V-Power 3/4" Reach 13/16" Hex Gasket, Loose Projected
BP6EY · BPR4EY · BPR5EY · BPR6EY · GR4 · GR5 V-Power 3/4" Reach 13/16" Hex Gasket, Solid Projected
BP8H-N-10 V-Power 1/2" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap
BPM6Y · BPM7Y · BPM7Y BL1 V-Power 3/8" Reach 3/4" Hex Gasket, Loose Compact, Projected
BPM8Y S25 SOLID · BPM8Y SOLID · BPMR6Y BL1 · BPMR7Y · BPMR8Y V-Power 3/8" Reach 3/4" Hex Gasket, Solid Compact, Projected
BPR5EY-11 · BPR6EY-11 · GR45 V-Power 3/4" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap
BPZ8H-N-10 V-Power 1/2" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap Inductive Resistor
BR6EB-L-11 V-Power 3/4" Reach 13/16" Hex Gasket, Solid Wide Gap
BR6EF · BR7EF V-Power .708" Reach 5/8" Hex Tapered, Solid
BR9EYA · BR10EYA V-Power 3/4" Reach 13/16" Hex Gasket, Solid
BUR6EA-11 · BUR7EA-11 V-Power 3/4" Reach 13/16" Hex Gasket, Solid Semi-Surface Discharge Wide Gap
FR4 · FR5 V-Power 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series
FR5-1 V-Power 3/4" Reach 5/8" Hex Gasket, Solid ISO Extended Projection Extended Shell Projection
FR45 V-Power 3/4" Reach 5/8" Hex Gasket, Solid ISO Projected FR-Series Wide Gap
LFR4A-E · LFR6A V-Power 26.5mm Reach 5/8" Hex Gasket, Solid Projected
LFR5A-11 · LFR6A-11 · LFR6C-11 V-Power 26.5mm Reach 5/8" Hex Gasket, Solid Projected, Wide Gap
LZTR4A-11 · LZTR5A-13 V-Power 25mm Reach 5/8" Hex Tapered, Solid Extended Projection Wide Gap
TR4 · TR5 · TR6 V-Power .708" Reach 5/8" Hex Tapered, Solid Projected
TR5-1 V-Power .708" Reach 5/8" Hex Tapered, Solid Projected Extended Shell
TR55 V-Power .708" Reach 5/8" Hex Tapered, Solid Projected, Wide Gap
TR55-1 V-Power .708" Reach 5/8" Hex Tapered, Solid Projected Extended Shell Wide Gap
UR4 · UR5 · UR6 V-Power .460" Reach 5/8" Hex Tapered, Solid Projected
UR45 · UR55 V-Power .460" Reach 5/8" Hex Tapered, Solid Projected, Wide Gap
XR4 · XR5 V-Power 3/8" Reach 13/16" Hex Gasket, Solid Projected
XR45 V-Power 3/8" Reach 13/16" Hex Gasket, Solid Projected, Wide Gap
YR5 V-Power .460" Reach 5/8" Hex Tapered, Solid
YR55 V-Power .460" Reach 5/8" Hex Tapered, Solid Wide Gap
ZFR4F-11 · ZFR5A-11 · ZFR5D-11 · ZFR5E-11 · ZFR5F-11 · ZFR5J-11 · ZFR6A-11 · ZFR6F-11 · ZFR6F-11G · ZFR6J-11 V-Power 3/4" Reach 5/8" Hex Gasket, Solid ISO Extended Projection Wide Gap
ZFR5F · ZFR5F-4 · ZFR5N · ZFR7F V-Power 3/4" Reach 5/8" Hex Gasket, Solid ISO Extended Projection
ZFR6K-9E · ZFR6U-9 · ZFR7F-11 V-Power 3/4" Reach 5/8" Hex Gasket, Solid ISO Extended Projection Wide Gap
ZGR5A-4 V-Power 3/4" Reach 13/16" Hex Gasket, Solid Extended Projection
ZGR5C V-Power 3/4" Reach 13/16" Hex Gasket, Solid Extended Projection Extended Shell

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