[ FOR HEX FASTENINGS ] Designed for use with hexagon hole fastenings. Use with in-hex screws or grub screws. [ EXTRA STRONG ] The impact socket is made from heavy duty chrome molybdenum (CR-MO) steel for exceptional strength and flexibility. [ LASTS FOR YEARS ] Black phosphate finish for maximum protection and durability. [ INSTANT IDENTIFICATION ] The impact socket features roll stamped markings to ensure permanent and instant socket identification. [ SAFE TO USE ] Designed for use with a locking pin and ring to increase safety when working with pneumatic tools.