Wera 05066670001 871/4 1/4'' Hex Torq-Set Mplus Power Drive Bits are the stronger flanks - when compared with the conventional TORQ-SET profile - result in 70% more breaking torque and thereby enhanced durability whilst at the same time providing a perfect fit in the screw head. Wera 871/1 1/4'' Hex Torq-Set Mplus Power Drive Bits are suitable for holders as per DIN ISO 1173-F 6.3.