This product is a 21 mm deep impact socket with a 1/2 inch square drive, designed to be used with pneumatic, electric or battery impact wrenches and hand drive tools where additional reach is required to access recessed or shoulder-mounted fasteners. Its primary use case is removal and tightening of hex-headed fasteners in situations where a standard shallow socket cannot reach.

The socket is manufactured from chrome–molybdenum (Cr–Mo) alloy steel and is heat-treated and tempered to withstand the high torque and shock loads produced by impact tools. The finish is a black phosphate/oxide coating that helps resist corrosion and minimises glare. The internal profile is a 6‑point (hex) configuration manufactured to industry-standard dimensions compatible with DIN/ISO/BS socket profiles, ensuring accurate fitment on hex fastener heads. The socket accepts a 1/2in (12.7 mm) square drive and is compatible with tools and extensions that use the standard detent ball or pin retention systems common to 1/2in drive accessories.

Typical applications include automotive wheel and suspension work, commercial vehicle maintenance, plant and machinery repair, agricultural equipment servicing and general industrial MRO tasks where deep access and impact-rated strength are needed. The deep length makes it particularly useful for stepped or long studs, recessed nuts and fasteners set over collars or washers.

Key benefits of this 21 mm impact deep socket are its material strength and impact toughness from the chrome–molybdenum construction, improved corrosion resistance from the black phosphate finish, and reduced likelihood of fastener rounding thanks to the accurate 6‑point profile. Compatibility with standard 1/2in drive impact wrenches, ratchets and extensions makes it a flexible addition to workshop toolkits, and the deep format extends usability compared with shallow sockets.

Draper Tools reference DR14104. Duchy Fasteners stocks this item and a broad range of impact sockets in metric and imperial sizes, available as single items or in sets and multi-packs to suit workshop and professional requirements.