Standard spark plugs are chosen by automotive, motorcycle, and marine engine manufacturers for their outstanding ability to increase performance while lowering ignition system voltage requirements. The unique copper core and exclusive electrode design ensure fast starts, peak performance, and a long life. Constructed with a triple gasket sealing process to eliminate gas leakage, the plugs feature a 99% highly pure alumina silicate insulator and solid copper core. Trivalent plating helps to prevent corrosion. Ensure fast starts & a long life Help eliminate gas leakage | NGK Standard Spark Plug, Part #IMR9D9H