The STEELMAN 06104 is fully compatible with 3/8-inch drive tools. Unlike similar sockets with two part construction, this socket is constructed from a single piece of durable chrome vanadium alloy steel for increased strength and durability. Hard stamped size markings are pressed directly into the steel and will not wipe off or wear away from even the most constant of use. A ball detent recess on the inside of the drive end helps hold the socket onto connected tools during use.