This 21mm spark plug socket with 1/2" drive is designed for larger spark plug applications, making it ideal for mechanics working on commercial vehicles, larger engines and specific vehicle makes that require this larger fitting. The 21mm size accommodates the bigger spark plugs commonly found in these applications. Manufactured from cold-forged Chrome Vanadium steel, this socket is hardened, tempered and chrome plated to deliver exceptional durability and corrosion resistance. The fully polished mirror finish not only looks professional but also resists dirt build-up, whilst the knurled ring provides secure grip even with oily hands. The integral socket insert is designed to grip the ceramic insulation of the spark plug, enabling safe extraction without risking damage to the delicate ceramic body. This feature proves particularly valuable when working with deep-seated plugs that are difficult to access in cramped engine compartments. Covered by Sealey's lifetime guarantee, this 21mm socket provides dependable performance throughout its working life. Features and Benefits: • 21mm size for larger spark plug applications • Cold-forged Chrome Vanadium steel with hardened and tempered finish • Chrome plated with fully polished mirror finish • Knurled ring for secure grip during operation • Socket insert protects ceramic insulation during plug removal • Especially useful for deep-seated plugs • Lifetime guarantee Specifications: Brand: Premier Drive: 1/2"Sq Material: Chrome Vanadium Nett Weight: 0.14kg Size: 21mm