Brisk GR12S Silver Racing spark plug for race car engines. Features a 14mm thread, 18mm (0.71in) reach, and 16mm (5/8in) hex with a tapered seat. Heat Range 12, resistor, with a silver center electrode for excellent heat dissipation and ignition in high-performance racing engines. Ideal for high-compression setups. Recommended torque: 15-22 ft-lbs. Gap: 0.020-0.035 inches. Sold as each.