NGK Standard Spark Plugs are treated with corrosion resistant plating to ensure ease of installation and removal. The 98% pure copper core delivers increased heat dissipation for more reliable starts and reduced risk of overheating. Cold-rolled threads prevent cross-threading and damage to cylinder heads. Trivalent plating eliminates need for anti-seize. Corrugated ribs prevent flashover. High-grade alumina silicate ceramic. Solid copper core for greater spark Longer insulator nose prevents fouling Corrugated ribs on insulator prevents flashover Zinc dipped shell prevents corrosion Triple gasket seal eliminates combustion gas leakage