TEKTON 1371 3/8-Inch Drive by 3/16-Inch Hex Bit Socket, Cr-V Precisely sized, chamfered tip inserts smoothly into fastener heads, reducing wear Detent notches in drive end lock onto ratchets and extensions Premium chrome vanadium steel bit has a black oxide finish that can't chip or flake Socket is forged from chrome vanadium steel with a mirror chrome-plated finish Size markings are permanently roll stamped