Representative Image NGK Iridium Plug Number KR8AI Spark Plug - 5477 Part #: 5477 Line: NGK NGK Iridium Plug Number KR8AI Spark Plug 1 Year Limited Warranty Seat: Gasket Thread Size: M12-1.25 Heat Range: 8 Hex Size (mm): 16mm Hex Size (in): 5/8 Inch Preset Gap (in): 0.032 Inch Preset Gap (mm): 0.8mm Thread Reach (in): 0.750 Inch Center Electrode Core Material: Copper Center Electrode Tip Material: Iridium Approximate Resistor Value (Ohm): 5000 Ohm Insulator Height (mm): 51mm Insulator Height (in): 2.010 Inch Thread Reach (mm): 19mm Service Number: KR8AI Metallurgy: Iridium Show More Show Less