554/ Teng TENM120512 M120512 Regular Bi-Hex Socket 12mm 1/2in Drive. Teng Tools specialises in a range of mechanics' hands tools to suit the price conscious professional user and the quality conscious DIY enthusiast. The Tools have been designed to Teng's own specifications, which meet or exceed British European or federal standards. This Teng Tools socket is a professional, bi-hexagon 1/2 inch square drive socket. It has been produced in accordance with ISO9000 and AS954 specifications for increased torque and reduced risk of rounding fasteners. Made from chrome vanadium steel for strength and durability, with a satin finish. The TENM120512 Bi-Hexagon, 12-point socket has the following specifications: Size: 12mm. Length: 38mm.