Whether you're working under the dashboard of a car, under the hood of a truck, trying to give your motorcycle a tune-up, or just trying to assemble some furniture, the STEELMAN 55503 T40 x 3/8-Inch Drive Star Bit Socket will help you get the job done. The rugged star / Torx bit head is machined from high-strength S2 steel to prevent twisting and deforming under high loads. The bit head is permanently set into a durable chrome vanadium steel socket with a rust and corrosion resistant, high polish chrome finish. For easy identification, the bit and socket have easy to read size markings hard stamped into the steel that won't wear off or fade away. To keep it securely attached to ratchets, extension bars, and adapters, the socket features a ball detent recess on the drive end and to ensure maximum torque transfer. The drive end also has 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, these tools can stand up to the rigors of any professional workshop while being just as handy in the home mechanic's garage.