This is a 21 mm impact socket with a 1/2" drive, designed for removing and tightening metric hex fasteners with impact tools. Its primary use is with 1/2" square-drive impact wrenches and breaker bars in workshops and on-site maintenance where repeated high-torque operations are required.

The socket is manufactured from chrome–molybdenum (Cr‑Mo) alloy steel and is heat treated to give high torsional strength and resistance to shock loading. The exterior finish is a black phosphate/oxide coating that offers improved corrosion protection and helps prevent surface galling under heavy use. The socket features a 6‑point (hex) internal profile to maximise contact with fastener flats and reduce the risk of rounding, and it accepts a 1/2" (12.7 mm) square female drive with a detent pin hole for secure retention on drive tools.

Dimensions and profiles conform to recognised industry dimensional standards for impact sockets (DIN/ISO/BS equivalent socket profiles), ensuring interchangeability with standard extensions, adapters and quick-release fittings. As an impact-rated tool, it is intended for use with pneumatic, hydraulic or battery-powered impact wrenches; its Cr‑Mo construction and heat treatment give superior fatigue life compared with standard chrome‑vanadium hand sockets.

Typical applications include tyre and wheel maintenance, commercial vehicle and agricultural machinery service, plant maintenance, construction equipment repairs and general workshop use. Industries that commonly use this 21 mm impact socket are automotive and fleet servicing, agricultural and earthmoving equipment workshops, industrial maintenance departments and motorsport teams where rapid, repeated nut removal and refitting is required.

Key benefits include enhanced resistance to shock and fracture under impact loading, improved corrosion protection from the black phosphate finish, and reduced fastener damage thanks to the 6‑point profile. The 1/2" drive ensures compatibility with a wide range of standard impact wrenches and extensions.

Duchy Fasteners stocks this 21 mm impact socket (DR26889) in bulk pack options and can supply individual sockets or metric sets across our impact socket range. Please contact us for available pack sizes and quantity pricing.