Stahlwille Bi-Hexagon Socket 3/8 in. Drive 11 mm. STW451145 Bi-Hexagon sockets, 3/8 in. drive. Manufactured from HPQ high performance steel, chrome plated. Manufactured to DIN 3124/ISO 2725-1, ASME B 107.5M, E DIN 3709. Size 11mm Overall length 27mm STW4511.