Champion tändstift RC9YCCopper Plus - Dependable Performance. Copper core center electrode allows for accurate control of heat range for longer life Patented TinTac and ULTRASEAL coated shell for maximum corrosion resistance Patented SAC-9 semiconductor resistor for maximum EMI & RFI suppression Built to ISO and SAE standards for proven performance Dependable performance. This Champion spark plug features a copper core electrode that provides increased conductivity and heat control for good overall wear.