05135079001 Tough viscous Wera 840/1 Z 1/4'' Hexagon Socket Head Bits for hexagon socket screws and universal use. The Wera 840/1 Z 1/4'' Hexagon Socket Head Bits offer 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. 1/4'' hexagon, suitable for holders as per DIN ISO 1173-D 6.3.