Spark Plug Application Commercial and Industrial Generators Lawn and Garden Hex Size 13/16 in Thread Size 0.551 in Thread Reach 0.375 in Ground Electrode Quantity 1 Ground Electrode Tip Design Standard Gap Size 0.028 in Resistor Plug Yes Hex Size - Metric 20.64 mm Thread Reach - Metric 9.53 mm Insulator Material Ceramic Manufacturer Heat Range 2 Seat Type Flat Center Electrode Diameter 0.098 in Ground Electrode Material Nickel Core Center Electrode Material Nickel