This is a 3/4" square drive 400mm extension bar designed to extend the reach of hand ratchets and torque wrenches so you can access recessed or awkwardly positioned fasteners. It provides a fixed-length extension between a 3/4" square drive ratchet and a compatible socket, allowing safer, more controlled torque application where direct access is not possible.

The extension bar is manufactured from chrome vanadium (Cr-V) steel and is heat treated and tempered to improve torsional strength and durability typical of professional hand tools. The polished chrome plated finish gives good corrosion resistance and eases cleaning in workshop environments. The bar features a 3/4" (19.05 mm) square female receptacle at one end and a 3/4" square male drive on the other, with a spring-loaded detent ball to securely retain sockets during use. The tool is produced to meet recognised DIN/ISO/BS hand-tool requirements for square drive socket accessories, ensuring dimensional compatibility with standard 3/4" sockets and drives.

Typical applications include heavy vehicle maintenance, plant and machinery servicing, agricultural and construction equipment work, rail and marine maintenance, and industrial assembly where fasteners are set back from accessible surfaces. The 400 mm length is especially useful for reaching into engine bays, gearboxes and equipment housings where a short breaker bar would not clear surrounding structures.

Key benefits of this extension bar include reliable socket retention provided by the detent ball, a corrosion-resistant chrome finish for extended service life in workshop or outdoor conditions, and a robust Cr-V construction that resists deformation under normal hand-tool torque loads. Compatibility with any standard 3/4" square drive sockets and ratchets makes it a flexible addition to a professional toolkit. Note: this bar is intended for hand-operated ratchets and torque wrenches; for impact tools use an extension specifically rated for impact duty (usually chrome-molybdenum construction).

Duchy Fasteners stocks this 3/4" square drive extension bar in single units and bulk packs. We also carry a comprehensive range of 3/4" extensions and couplers in lengths from short adapters to long reach bars, plus matching sockets and accessories to suit workshop and industrial applications.