Hex key Proline 4 mm — 1 pc (model 48444)

Proline 4 mm hex key (single piece) is a compact hand tool designed for tightening and loosening metric M4 hex (Allen) fasteners. Manufactured from quenched and tempered steel with a polished chromium finish, this hex key combines strength and corrosion resistance while preserving a slim profile for access in confined spaces. The single 4 mm size offers precise torque control for assembly and maintenance tasks where M4 fasteners are specified.

Advantages

The hardened and tempered steel construction provides durability and resistance to bending under regular torque loads. Polished chromium finishing improves surface protection against corrosion and makes the tool easier to clean after use. Its compact, single-piece design ensures straightforward handling and storage while allowing access to tight or recessed fasteners. The accurate 4 mm tip geometry ensures a secure fit with hex socket heads to minimize rounding.

Suitable for

• Furniture assembly and disassembly using M4 hex fasteners
• Bicycle maintenance where 4 mm Allen keys are required
• Electronics and appliance maintenance with small metric hex screws
• General mechanical repairs and precision fastening tasks

Key specifications

• Size: 4 mm (metric)
• Quantity: single piece
• Material treatment: quenched and tempered steel
• Surface finish: polished chromium
• Tool type: straight hex (Allen) key
• Intended fastener: M4 hex socket heads

How to use

Insert the 4 mm hex key into the corresponding hex socket of the fastener, ensuring full engagement of the tip. Apply steady torque, using a longer lever arm where more torque is needed and the shorter end for confined spaces or finer control. Avoid excessive force beyond the recommended torque for M4 fasteners to prevent tool or fastener damage. After use, wipe the tool clean and store it in a dry place to maintain the polished chromium finish.

Usage recommendations

Use this 4 mm Proline hex key for repetitive tasks with M4 fasteners, and pair it with an appropriate torque specification or torque-limiting device when working on components sensitive to overtightening. Inspect the tip periodically for wear and replace the tool if the tip becomes rounded to ensure continued secure engagement.