The product is a set of 8 original OEM 12639701 glow plugs designed to fit specific models of LMM, LML, and LBZ Silverado and Sierra Duramax trucks. Manufactured by ACDelco, these high-quality glow plugs are a direct replacement for the original part and are suitable for diesel vehicles. With a new and durable surface finish, these glow plugs are a reliable choice for improving the ignition system of your vehicle.