NGK nickel spark plugs feature a specially designed v-groove center electrode, improving ignitability and reducing quenching. The 98% pure copper core delivers increased heat dissipation for more reliable starts and reduced risk of overheating. Features: High-grade alumina silicate ceramic Creates a stronger insulator to reduce dielectric punchthrough (caused by spark exiting through side of ceramic) Cold rolled threads Prevents cross-threading and damage to cylinder heads 98% pure copper core Increased heat dissipation for reliable starts, prevents spark plug overheating Trivalent metal plating No anti-seize required Ground electrode Designed to reduced quenching effect resulting in better ignition performance DS 250 2006-2018