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