These Faithfull S2 Grade Steel Screwdriver Bits have the following specification: Size: PZ2 x 25mm Pack Quantity: 25 These Faithfull professional 1/4in Hex Drive Pozidriv Screwdriver Bits are manufactured from high strength, heat-treated S2 grade steel. Bits are shock and wear resistant and feature precision machined tips to provide an optimum fit, helping to prevent screw stripping and cam-out and provide a long working life.