14 mm thread Dia, 3/4 in reach, 13/16 in hex socket. Quicker starts, Saves on fuel and reduces emissions. Replaces Champion N4C, N5C, N7YC, RN4C, RN5C, RN7YC. Replaces Autolite 403, 404, 4055, 4056, XST4055. Replaces NGK B4ES, B5EB, B5ES, BEV, B6EB, B6EB11, B6ES, B6ES11, B6EB, B7EB, B7EB11, BP7ES, BP7ES11, BPR7ES, BPR7ES11, BR4ES, BR5EB, BR5ES, BR6EB, BR6EB11, BR6ES, BR6ES11, BR7EB11, BUR7EA11, BUR7EB11.

California residents see Prop 65 WARNINGS