Best Way Tools 9pc Metric Nut-setter set has a 1/4" hex shank drive, fits all sizes of cordless or cordless drill drivers, and screwdrivers. Sizes includes 5.5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, and 13mm. The bit is made from tool steel and is heat treated to give it maximum life. Blast finish increases the gripping power to reduce cam out. The set comes with a tool holder marked with sizes for easy storage. Deep printing on the socket base identifies tool and won't wear off over time.