Teng M140512 Hexagon Socket 6 Point Regular 1/4in Drive 12mm Size. 12mm. A professional matt chromed 1/4in square drive socket, produced in accordance with ISO 9000 and AS954 specifications, for increased torque and reduced risk of rounding fasteners. This hexagonal socket has a relatively short depth and a stepped collar on the shank. Overall Length: 24mm. Size. 12mm.