US PRO Tools 1/2" DR Impact Hex Bit Socket M5 X 78MM 3364. This impact hex bit socket is made from chromium-vanadium steel for strength and durability, with an industrial black oxide finish to resist abrasion, oxidation, and corrosion. It features a 1/2" drive, suitable for use with any 1/2" drive ratchets, bars, or extensions. The socket size is 5mm and the length is 78mm.