Genuine Champion Spark Plug Part # 849C 

Specifications:

Thread Diameter: 14mm
Thread Pitch: 1.25mm
Seat Type: Gasket
Reach: 9.5mm (3/8")
Hex Size: 3/4" (19mm)
Terminal Type: Removable Nut
Gap: .024" (0.6mm)

Applications: Fits: EH561, Pro-Mac, L1LJ, M36, M361, 2100CDW, 2100CW, 1010, 1130G, 35SL, VI123, GA10075, 350CS, M361AV, AL42, AL51, 35375, 35376, 35883, SL2, SL21, Super XL-925, Super XL-AO, XL924A & more