NGK DPR6EB-9 (3108) 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 Thread Size: 12mm Thread Pitch: 1.25mm Seat Type: Gasket Resistor Value: 5K Ohm Reach: 19mm (3/4") Hex Size: 18mm Terminal Type: Solid Overall Height: ISO Gap:.035" (0.9mm)