Autolite Copper Resistor Spark Plug Autolite Copper Core spark plugs deliver quick starts good fuel economy and smooth acceleration. The copper-glass seal bonded insulator terminal post and center electrode ensure a tight seal that is 100 percent leak-proof and the full copper core electrode improves heat transfer and optimizes plug life. Copper Core spark plugs feature high alumina ceramic for high dielectric strength and a steel shell for installation robustness. The multi-rib insulator reduces the danger of flash-over to prevent misfires and the copper core center electrode provides higher thermal conductivity. These spark plugs are engineered with a high nickel alloy center and ground electrode for extended life. Features and Benefits: Copper-glass seal bonded insulator terminal post and center electrode provide a tight seal that is 100 percent leak-proof Multi-rib insulator reduces danger of flash-over to prevent misfires Full copper core electrode improves heat transfer and optimizes plug life Copper core center electrode provides higher thermal conductivity Features high alumina ceramic for high dielectric strength and steel shell for installation robustness