NGK Standard spark plugs are chosen by more automotive, motorcycle, and marine engine manufacturers than any other spark plugs available. The unique copper core, 99% highly pure alumina silicate insulator, and exclusive electrode design ensure fast starts, peak performance, and long life. Triple gasket sealing process eliminates gas leakage past the shell. Corrugated ribs prevent flash over, while cold rolled threads help protect cylinder head. Trivalent plating includes silver chromate and zinc for corrosion resistance.