Standard spark plugs are chosen by more automotive, motorcycle, and marine engine manufacturers than any other. The unique copper core and exclusive electrode design ensure fast starts, peak performance, and long life. Superior construction features high-alumina ceramics, deep-seated copper core, and nickel alloy tip. Triple gasket sealing process eliminates gas leakage past the shell. Corrugated ribs prevent flash-over. Cold rolled threads prevent damage to cylinder head. Trivalent plating includes silver chromate and zinc for corrosion resistance. Triple gasket sealing eliminates gas leakage Trivalent plating offers corrosion resistance | NGK Plug, BKR6EKU in Silver