Copper Plus - Dependable Performance and Durability Copper core center electrode allows for accurate control of heat range for longer life Superior corrosion resistance Built to ISO and SAE standards for proven performance Durable: Champion copper plus spark plugs are built to ISO and SAE standards for proven performance; Champion's patented SAC-9 semi-conductor resistor provides maximum EMI and RFI suppression Champion copper plus spark plugs use TinTac and Ultraseal Shells, this eliminates the need for the use of anti-seize compound during installation by providing the best corrosion protection of any spark plug in the industry The Champion copper plus spark plug features a copper core electrode that provides increased conductivity and heat control while delivering good overall wear characteristics Provides longer life; Copper core center electrode allows for accurate control of the plug's heat range, optimizing the plug's performance and adding to the longevity of the spark plug