NGK Racing Series plugs are engineered to withstand the harshest engine conditions. Fine wire iridium tipped center electrode improves ignitability, increases durability, and enhances anti-fouling capabilities. Special insulator nose configurations improve throttle response. Corrugated ribs prevent flashover. Pure alumina silicate ceramic insulator, provides superior strength and better heat transfer. Copper core aids in heat removal. Triple seals prevent leakage.