The Irwin Impact Screwdriver Bits are specifically designed for use in high torque impact drivers. They are manufactured from heavy-duty, high-grade steel and have a 3 times increased life compared to standard screwdriver bits. Their precision tip geometry delivers superior fitment, reducing stripping and cam-out. The bits are Power Groove designed for compatibility with IRWIN® Impact Performance Series™ magnetic screw-hold attachment. This set contains the following:7 x Phillips 25mm bits: PH1 x 2, PH2 x 3 and PH3 x 2.7 x Pozi 25mm bits: PZ1 x 2, PZ2 x 3 and PZ3 x 2.7 x Torx 25mm bits: T20 x 3, TX25 x 2 and T30 x 2.5 x Phillips 50mm bits: PH2.5 x Pozi 50mm bits: PZ2.1 x 3in bit holder. Supplied in a moulded ABS resin case.