NGK's Standard Plugs are Constructed for Longer Life and Optimum Performance. - 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