NGK ZFR6K11 Spark Plug Thread Diameter: 14mm Thread Pitch: 1.25mm Seat Type: Gasket Thread Reach: 19mm (3/4") Hex Size: 16mm (5/8") Terminal Type: Solid Electrode Gap: 1.1mm (.043") Center Electrode Material: Nickel, V-Cut, 2.5mm Projection: Projected Ground Electrode Material: Nickel, standard trapezoid shape Resistor Value: 5k Ohm Heat Range: 6 Torque Specs: 18-25.3 lb. ft. for cast iron, 18-21.6 lb. ft. for aluminum