NGK's Laser Iridium Spark Plugs Provide Superior Ignitability and Long Service Life. Fine Wire Iridium Tipped Center Electrode and Fine Wire Platinum Tipped Ground Electrode Ensures Slow Wear Rate Providing Stable Idle, Superior Anti Fouling, Improved Fuel Efficiency and Lower Emissions. Trivalent Metal Plating Provides Superior Anti-Corrosion and Anti-Seizing Properties Corrugated Ribs Prevent Flashover Pure Alumina Silicate Ceramic Insulator, Provides Superior Strength and Better Heat Transfer Copper Core Aids in Heat Removal Triple Seals Prevent Leakage