Trivalent Metal Plating Provides Superior Anti-Corrosion and Anti-Seizing Properties Corrugated Ribs Prevent Flash-over Pure Alumina Silicate Ceramic Insulator, Provides Superior Strength and Better Heat Transfer Copper Core Aids in Heat Removal Triple Seals Prevent Leakage Thread Size: 14mm Thread Pitch: 1.25mm Seat Type: Tapered Resistor: YES – 5 K Reach: 3/8″ (9.5 mm) Hex Size: 3/4” (19 mm) Gap:.04″ (1.0 mm) A spark plugs’ tip temperature and the voltage necessary to fire the plug are directly affected by the gap setting. Setting the gap for your particular engine is important. Insufficient spark plug gap can cause pre-ignition, detonation and in some cases engine damage. If gap is to BIG ,can result in a higher rate of misfires, loss of power, plug fouling and poor fuel economy.