Whether you're working on a car or assembling furniture, the STEELMAN 55491 3/8-Inch Drive x 4mm Metric Hex Bit Socket delivers the dependable grip you need. With a hex bit machined from high-strength S2 steel to prevent twisting and deformation of the socket under high loads set into a durable chrome vanadium steel socket, this tool is designed for long-term service. For easy identification, the socket has easy to read size markings permanently stamped into the steel that won't wear or fade away. To keep securely attached to ratchets, extension bars, and adapters, this socket features a ball detent recess on the drive end and to ensure maximum torque transfer. The drive end is also designed with corner recesses that transmit applied force to the flats instead of focusing on the corners which can lead to slippage, rounding, and premature tool failure. Designed and constructed to meet or exceed ASME tool performance standards, this tool can stand up to the rigors of any professional workshop while being just as handy in the home mechanic's garage.