The 21mm Sealey 3/8" Drive Hexagon Spark Plug Socket is designed for larger spark plug applications, making it ideal for working on performance vehicles, larger engines, and specialist automotive applications. This cold-forged Chrome Vanadium steel socket delivers professional-grade performance with exceptional durability. The 21mm configuration accommodates the larger spark plug sizes found in many modern engines, particularly in performance and commercial vehicle applications. Hardened and tempered for maximum strength, the socket features a chrome plated finish that resists corrosion and maintains its appearance even after extensive use. The fully polished mirror finish combined with the knurled ring provides excellent grip and control during operation. The specialist socket insert is engineered to grip the ceramic insulation of spark plugs, ensuring safe removal and installation without risk of cracking or damaging the delicate ceramic components. This feature is especially beneficial when working with deep-seated plugs in hard-to-reach engine compartments. Features and Benefits: • 21mm size suits larger spark plug specifications • 3/8" drive compatible with standard tool sets • Hardened Chrome Vanadium steel for lasting performance • Ceramic-gripping insert for safe plug handling • Knurled ring ensures secure grip • Lifetime guarantee* for confidence • Model No. S38SP14 Specifications: Brand: Premier Depth: Deep Drive: 3/8"Sq Material: Chrome Vanadium Nett Weight: 0.14kg Size: 21mm