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. The information below is per-pack only Solid copper core for greater spark Longer insulator nose prevents fouling Corrugated ribs on insulator prevents flashover Zinc dipped shell prevents corrosion