BOSCH PREMIUM CLASS PLATINUMIR FUSION SPARK PLUG -- Iridium platinum, 14 mm thread, 19 mm reach, 16 mm hex size, gasket seat, interference suppression resistor, surface air gap plug, 4 ground electrodes, iridium-platinum fused center electrode, heat range 8; Fuses iridium with platinum and combines the superior properties ob both materials into a single fine wire center electrode; Uses surface air gap technology and 4 yttrium enhanced ground electrodes for both performance and extra long life; Reduces the voltage necessary to jump the gap as well as reduces quenching; Provides multiple radial spark paths and surface air gap design that creates optimal exposure of the air/fuel mixture to the enhanced ignition spark; Designed to give exceptional performance, reach self cleaning temperature faster for quicker starts, smoother acceleration and increased fuel efficiency.