OBD1663 Features: * Hardened for extra strength * ""Lobular"" design exerts force on flats of fasteners * Chamfered opening slips easily over fasteners and holds securely * Prevents rounding of fasteners" corners * Thin wall design fits into tight spots * Through hole in drive square for secure attachment to power drivers * Drive Size: 1/2 in * Drive Type: Square * Material: Cold Formed Steel * Testing and approvals: * Meets ANSI Spec. B107.1 * Meets Federal Standards GGG-W-641e * Meets ANSI B107.5m