This is a genuine Champion XEJ-8 spark plug stock # is 557.  It has been discontinued, buy this one before it gone. 
Copper-cored nickel center electrode with basic J-gap ground for optimum ignitability. Lower voltage requirement than precious metal plugs. Shielded 5/8-24 connector for hazardous location use.

  • Product Specifications
    • Shell
    • Thread Diameter14mm
    • Thread Pitch1.25mm
    • Seat TypeGasket
    • Reach9.5mm (3/8")
    • Hex Size7/8" (22mm)
    • Terminal TypeShielded
    • Gap.026" (0.65mm)
    • Center Electrode
    • MaterialNickel
    • TypeStandard
    • Size2.3mm
    • ProjectionNon-Projected
    • Ground Electrode
    • MaterialNickel
    • TypeStandard
    • Quantity1
    • Specifications
    • ResistorYes
    • Resistor TypeShielded
    • Heat Range8
    • FeaturesShielded 5/8-24 Connector
    • Torque SpecsCast Iron: 26-30 lb. ft. Aluminum: 18-22 lb. ft.
    • Part Information
    • BrandChampion
    • Replacement GasketN678