ACCEL Spark Plug Spark Plug - 8161C1 Part #: 8161C1 Line: ACC ACCEL Spark Plug Spark Plug 90 Day Limited Warranty Seat: Tapered Thread Size: M12 Hex Size (in): 9/16 Inch Thread Reach (in): 1.040 Inch Resistor Plug: Yes Center Electrode Core Material: Copper Center Electrode Tip Material: Copper Metallurgy: Copper Show More Show Less