Thread Diameter and Hex Size < Thread Diameter x Hex Size > (mm) M --- 18 x 25.4 (Reach: 12mm) L --- 18 x 22.2 (Reach: 12mm) MW --- 18 x 20.6 (Reach: 12mm) MA --- 18 x 20.6 (Tapered seat, Reach: 12mm) FK+ --- High Ignitability Plug (0.55mm Ir center electrode, Pt ground electrode) J* --- 14 x 20.6 (Projected plug) K+ --- 14 x 16.0 (Miniature plug) KJ*+ --- 14 x 16.0 (Projected miniature plug) LP* --- 14 x 20.6 (Plug for LPG applications) P* --- 14 x 20.6 (Platinum plug) PK* --- 14 x 16 (Miniature platinum plug) PKJ* --- 14 x 16 (Projected miniature platinum plug) PQ* --- 14 x 16 (Miniature platinum plug) Q* --- 14 x 16 (Miniature plug) QJ* --- 14 x 16.0 (Miniature projected plug) QL* --- 14 x 20.6 (Miniature long cylinder housing plug) S* --- 14 x 20.6 (0.7mm diameter iridium) S --- 14 x 20.6 (Surface gap plug (for RE engines)) SK+ --- 14 x 16 (0.7mm diameter miniature iridium plug) SKJ*+ --- 14 x 16 (Projected 0.7mm diameter miniature iridium plug) SV --- 0.4mm diameter iridium with platinum ground electrode T --- 14 x 16.0 (Tapered seat) TR@ --- 14 x 20.6 (For marine applications) W --- 14 x 20.6   --- 14 x 19.0 (Compact type) X --- 12 x 18.0 XE --- 12 x 14.0 XU --- 12 x 16.0 U --- 10 x 16.0 U --- 10 x 14.0 (U20M-U Only) N --- 10 x 16.0 Y --- 8 x 13.0 Z --- 1/2PF x 23.8 Z --- 0.55 mm diameter iridium * --- Reach: 19.0 + --- ISO compatible @ ---Reach: 12.7

Heat Range DENSO NGK CHAMPION BOSCH 9 2 18 10 14 4 16,14 9 16 5 12,11 8 20 6 10,9 7,6 22 7 8,7 5 24 8 6,63,61 4 27 9 4,59 3 29 9.5 57   31 10 55 2 32 10.5 53   34 11     35 11.5

Reach A --- 19mm (Electrode position: 7mm)   --- 21.5mm B --- 19.0mm (Electrode position: 9.5mm) C --- 19.0mm (Electrode position: 5.0mm) D --- 19.0mm (Shroud: 2mm) E (With gasket) --- 19.0mm 20.0mm E (Taper seat) --- 17.5mm F --- 12.7mm FE --- 19.0mm (Half thread) G --- 19.0mm (Shroud: 2.8mm)   --- 19.0mm (Shroud: 3.0mm) H --- 19.0mm (Electrode position: 8.5mm)   --- 26.5mm L --- 11.2mm M --- 8.6mm N (Taper seat, HALF THREAD) --- 17.5mm V (Tapered seat) --- 25.0mm None --- 9.5mm 11.2mm 19.0mm 21.5mm None (Tapered seat) --- 8.3mm 11.2mm 11.2mm

Shape (Type) A --- Double ground electrodes A --- Oblique ground electrode (For racing) AY --- Double ground electrodes with bent shape (special) B --- Triple ground electrodes BG --- Triple ground electrodes (shrouded) D --- Quadruple ground electrodes K --- 1mm Insulator projection LM --- Compact type (Hex size: 20.6mm) M --- Shortened insulator head length M --- Compact type (Hex Size: 19.0mm) N --- Racing type (Nickel electrode) Pt --- Racing type (Platinum electrodes) P --- Projected (1.5mm projection) S --- Non-projected (0mm projection)   --- Iridium on a single side T --- Double ground electrodes TM --- Double ground electrodes TN --- Double ground electrodes V --- Slant ground electrode X --- Fully projected (2.5mm projection)

Internal Construction R --- With Resistor None --- Without Resistor < Exception > S29A, S29 both have Resistors

Shape (Type) -A --- Special specification -B --- Special specification -C --- Cut-back ground electrode -E --- Special specification -F --- Special specification -G --- Grease applied on to threads, for CNG applications -GL --- Platinum center electrode -L --- For CVCC, with a withdrawn insulator   --- 3.5mm projected insulator for motorcycles   --- Withdrawn insulator for motorcycles   --- Thin center electrode for motorcycles   --- Heat resistant ground electrode -M --- Larger ground electrode -N --- For Yamaha and Kawasaki -P --- Ground electrode has a double layer of platinum   --- Center or ground electrode has platinum -S --- Semi-surface gap discharge type -S --- Stainless gasket -TP --- Platinum on center electrode, with taper cut ground electrode -U --- U-cut ground electrode -US --- Star-shaped center electrode is used -V --- 0.7mm diameter platinum alloy center electrode -Z --- Taper cut -ZU --- ZU Plug

Gap 5 --- 0.5mm (.020'') 8 --- 0.8mm (.032'') 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'') < None > Cars: 0.8mm M.C: 0.7mm < Exceptions > P16R, PQ16R, PQ20R are 1.1mm