Socket bit hex Allen 1/2" H4 x 55 mm STANLEY STMT73371-8B

STANLEY 1/2" drive hex (Allen) socket bit H4 x 55 mm is a tool insert designed for use with 1/2" drive ratchets, torque wrenches and compatible impact drivers. The bit provides a 4 mm internal hex profile and a 55 mm overall length to reach recessed or deep-set hex fasteners commonly found in mechanical, automotive and assembly applications. Manufactured for compatibility with standard 1/2" drive sockets, this hex socket bit offers a compact profile for confined spaces and routine maintenance tasks.

Advantages

The socket bit combines a standardized 4 mm internal hex geometry with a 55 mm shaft length to improve access to recessed fasteners while maintaining a secure fit with 1/2" drive tools. Its design reduces cam-out risk and enables reliable torque transfer when used with torque-controlled tools. The bit's length and drive interface make it suitable for tasks that require both reach and stable connection to drive tools.

Suitable for

• Accessing recessed hex (Allen) screws and bolts in mechanical assemblies
• Automotive repair and maintenance where a 4 mm internal hex is required
• General assembly, disassembly and routine service tasks in workshops
• Use with 1/2" drive ratchets, torque wrenches or compatible impact drivers

Key specifications

• Drive type: 1/2" square drive compatible socket bit
• Tip profile: 4 mm internal hex (Allen)
• Overall length: 55 mm
• Material and finish: engineered for tool-grade durability (manufacturer standard)
• Compatibility: fits standard 1/2" drive tools and socket adapters

How to use

Select the STANLEY 4 mm hex socket bit and attach it securely to a 1/2" drive ratchet, torque wrench or impact driver designed to accept socket bits. Align the internal hex tip with the fastener head, apply axial pressure to seat the tip, then rotate using the chosen drive tool. When using a torque wrench, set the required torque value before applying force. For impact driver use, ensure the driver and bit are rated for impact operation if required by the task.

Usage recommendations

Use the bit with the appropriate drive tool and torque setting for the fastener size to avoid rounding the hex recess. Inspect the bit for wear or deformation before use and replace it if signs of damage appear. For operations requiring high torque, confirm compatibility with impact-rated tools and adapters to maintain safe and effective performance.