NGK Spark Plug Resistor Cover - SD05F. This one is a straight long style. For 12mm or 10mm thread spark plugs without the terminal stud. We recommend using non-resistor type spark plugs when using resistor caps. Fits any bike as long as you have 7mm spark plug wires and enough clearance. Overall length 3.7" (94mm) with rubber attached. These fit the inner cylinders 2 and 3 on the SOHC Honda CB750's. NGK spark plug resistor covers are the best protection against radio frequency interfer