Brisk HR15YS Silver Racing spark plug for race car engines. Features a 14mm thread, 12.7mm (1/2in) reach, and 16mm (5/8in) hex with a tapered seat. Heat Range 15, resistor, with a silver center electrode for superior heat transfer and ignition in high-performance racing engines. Ideal for high-performance turbo or nitrous setups. Recommended torque: 15-22 ft-lbs. Gap: 0.020-0.035 inches. Sold as each.