Arnold E3.18 Spark Plug, 13/16 in Fill Gap, 0.551 in Thread, 13/16 in Hex

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.