NGK (4772) DR9EIX Iridium IX Spark Plug, Pack of 1 Designed to operate over a much wider heat range than ordinary plugs Resists carbon buildup and pre-ignition High alumina ceramics for better heat transfer and electrical insulation Solid copper core and nickel tipped electrode provide a longer plus life Patented triple gasket sealing process eliminates the possibility of combustion gas leakage Designed specifically for the performance enthusiast, Iridium IX offers extreme ignitability, improved throttle response and superior anti-fouling The 0.6mm laser welded fine Iridium tip ensures high durability and a consistently stable spark and the tapered ground electrode minimizes electrical quenching effect Longer insulator nose prevents fouling, the corrugated ribs on insulator prevents flashover, and a triple gasket seal eliminates combustion gas leakage Iridium alloy has extremely high melting point, giving it high durability to heat and electrical wear, perfect for today's high-performance engines Trivalent metal plating has superior anti-corrosion and anti-seizing properties