The Spark Plug Serious Enthusiasts Rely On Designed specifically for the performance enthusiast. Iridium IX® offers extreme ignitability, improved throttle response and superior anti fouling Fine Iridium tip ensures high durability and a consistently stable spark Iridium alloy has extremely high melting point, perfect for today’s high-tech, high-performance engines Trivalent Metal Plating - superior anti-corrosion and anti-seizing properties Outstanding acceleration, high fuel efficiency and durability Ultimate design, technology and performance.