The NGK Iridium IX offers extreme ignitability, improved throttle response and superior anti fouling properties. The Iridium alloy has extremely high melting point, ensuring high durability and a consistently stable spark that is perfect for today's high-tech, high-performance engines. NGK's IX Iridium Series Plugs were Designed Specifically for the Performance Enthusiast Designed specifically for the performance enthusiast. Product Features:Fine Wire Center Electrode Ensures High Durability and a Consistently Stable SparkIridium Alloy has an Extremely High Melting Point, Perfect for Today's High-Tech, High Performance EnginesTrivalent Metal Plating Provides Superior Anti-Corrosion and Anti-Seizing PropertiesCorrugated Ribs Prevent FlashoverPure Alumina Silicate Ceramic Insulator, Provides Superior Strength and Better Heat TransferCopper Core Aids in Heat RemovalTriple Seals Prevent Leakage