Wera 05057604001 840/1 IMP DC Impaktor 1/4'' Hex Socket Insert Bit for hexagon socket screws. The Impaktor technology offers an above-average service life even under extreme circumstances. The Wera 840/1 IMP DC Impaktor 1/4'' Hexagon Socket Head Bit's enhanced friction resistance, thanks to the rough diamond-particle coating on the bit tip, prevents any slipping out of the screw head. Hex-Plus ensures 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.