DENSO SPARKPLUG

Thread and Hexagon size	Heat Range	Thread Reach	Special Design	Internal Construction	Special GAP configuration	Gap

	Thread and Hexagon size Letter Thread Size Hex. size Description L 18mm 22.0mm   M 18mm 25.4mm   MA 18mm 20.8mm Taper seat *J 14mm 20.8mm Extended electrodes *P 14mm 20.8mm Platinum-tipped electrodes *PQ 14mm 16.0mm Platinum-tipped electrodes *Q 14mm 16.0mm   *QJ 14mm 16.0mm Extended electrode *K 14mm 16.0mm ISO *KJ 14mm 16.0mm ISO *PK 14mm 16.0mm Platinum-tipped electrodes S 14mm 20.8mm Special surface gap for Mazda RE/thread reach 21.5mm SF 14mm 20.8mm Surface gap *SK 14mm 16.0mm Iridium-tipped centre electrode Platinum-tipped ground electrode T 14mm 16.0mm Taper seat W 14mm 20.8mm   TR 14mm 20.6mm Thread reach 12.7mm X 12mm 18.0mm   XU 12mm 16.0mm   U 10mm 16.0mm   Y 8mm 13.0mm   *These letters indicate including thread reach 19.0mm.
	Heat Range
	Thread Reach Letter Reach Description E (Flat seat) 19.0mm (3/4") or 20.0mm W16EXR-U W25EBR E (Taper seat) .708" T16EPR-U F 12.7mm (1/2") W20FP-U FE 19.0mm (3/4") Half thread U24FER9 G 21.8mm X27GPR-U L 11.2mm (7/16") W14L None     18mm thread (Flat seat) 12.0mm M24S, L14-U 14mm thread (Flat seat) 9.5mm (3/8") W20S-U, W9PR-U 18mm thread (Taper seat) .480" MA16PR-U 14mm thread (Taper seat) .460" or .325" T16PR-U T20M-U/WA20M-U
	Special Design Letter Description Example A Dual ground electrodes for Mazda RE W22EA *A Electrode projection (7.0mm) QJ16AR-U B Triple ground electrodes W20EPB *B Electrode projection (9.5mm) J16BR-U *C Electrode projection (5.0mm) QJ20CR11 D 4-ground electrodes for Mazda RE W27EDR14 *H Electrode projection (8.5mm) QJ16HR-U K Special type for Honda CVCC W16EKR-S11 LM Special type for lawn mowers W14LM-U M Compact type W20M-U N Racing type (nickel ground electrode) W27EN PT Racing type (platinum ground electrode) W27EPT P Project insulator nose W16EP-U S Regular type W24ES-U T Dual ground electrodes for Toyota T.G.P. W20ET-S X Extra projected insulator nose W16EX-U *When the first suffix is J or QJ/KJ.
	Internal Construction Letter Description None Non resistor R Resistor
	Special GAP configuration Letter Description Example GL Platinum center electrode X22EPR-GL L Special type for Honda and extra project type for moped KJ20CR-L11 W14FP-Ul S Semi-Surface gap W20EPR-S11 U U-groove ground electrode W16EX-U US Star centre electrode with U-groove W14-US V Thin centre electrode W24ES-V Z Thin platinum centre electrode with tapered ground electrode W24ES-ZU C Cut-back ground electrode W27EMR-C P Platinum-tipped plug for DIS PQ20R-P8
	Gap Letter Gap 9 0.9mm (.035") 10 1.0mm (.040") 11 1.1mm (.044") 13 1.3mm (.050") 14 1.4mm (.055") 15 1.5mm (.060") 20 2.0mm (.080")

SPARK GAP	inch	.020	.024	.028	.032	.035	.040	.044	.048	.060	.080
	mm	.05	0.6	0.7	0.8	0.9	1.0	1.1	1.2	1.5	2.0