Hex Key Set c.k tools T4422 — Metric 4 mm

The Hex Key Set c.k tools T4422 — Metric 4 mm offers a single, precision 4 mm hex key intended for turning internal hex fasteners. Designed for workshop and DIY use, this compact tool provides a close fit to 4 mm internal hex bolts and screws and is suitable for assembly, maintenance and repair tasks that require a reliable single-size hex driver.

Advantages

The 4 mm metric hex key is made to provide accurate engagement with 4 mm hex sockets, reducing rounding and slippage when applying torque. Its compact format makes it easy to store in a toolbox or carry on a belt, while the simple, rigid construction ensures consistent alignment and force transfer. The single-size configuration simplifies selection for tasks that only need a 4 mm driver, avoiding clutter from multi-piece sets.

Suitable for

• Assembly of furniture and fixtures with 4 mm internal hex fasteners
• Maintenance and repair of bicycles, appliances, and machinery using 4 mm hex bolts
• Electronics and hobbyist projects requiring a precise 4 mm hex driver
• Workshop and domestic DIY tasks where a dedicated 4 mm tool is preferred

Key specifications

• Tool type: single metric hex key (Allen key)
• Size: 4 mm (across flats)
• Material: hardened steel construction for wear resistance (typical for hex keys)
• Finish: corrosion-resistant coating or treatment to extend service life
• Form factor: L-shaped for leverage and reach

How to use

Insert the short or long arm of the 4 mm hex key fully into the internal hex socket of the fastener to ensure full contact on all faces. Apply steady torque, using the long arm for greater leverage when loosening or tightening and the short arm for confined spaces or higher torque control. Keep the key perpendicular to the screw axis to minimize cam-out and wear on both tool and fastener. Inspect the hex faces before use and replace the key if rounded or damaged.

Usage recommendations

For best results, match the 4 mm hex key precisely to the fastener size and avoid excessive force that may deform the hex profile. Use appropriate personal protective equipment when working with hand tools, and store the key in a dry location to prevent corrosion. For high-torque applications consider using the long arm for leverage or a different tool designed for higher torque limits.