The 05057520001 Wera 840/2 Z 5/16'' Hexagon Socket Head Bit is a tough viscous Wera bit for hexagon socket screws for universal use. Hex-Plus offers a greater contact surface in the head of the screw. The notching effect is therefore reduced to a minimum and damage to the screw head more or less eliminated. 5/16'' hexagon, suitable for holders as per DIN ISO 1173-D 8.