851/4 IMP DC PH DIY Impaktor PH bits, PH 3 x 50 mm, 5 pieces 5x 851/4 IMP DC Impaktor bits: PH 3 x 50 mmHigh quality bits for Phillips screws. The Impaktor technology offers an above-average service life even under extreme circumstances. Enhanced friction resistance, thanks to the rough diamond-particle coating on the bit tip, prevents any slipping out of the screw head. Particularly suitable for use with customary impact drivers. hexagon, suitable for holders as per DIN ISO 1173-F 6.3.