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. Cold-rolled threads prevent cross-threading and damage to cylinder heads. Trivalent plating eliminates need for anti-seize. High-grade alumina silicate ceramic insulator. Triple seals prevent leakage.