The Irwin Hex Impact Screwdriving Bits are specifically engineered for use in high torque Impact Drivers. They are manufactured from heavy-duty, high-grade steel and have a 3x increased bit life compared to standard screwdriver bits. The screwdriver bits have precision tip geometry that delivers superior fitment, reducing stripping and cam-out. They have a Power Groove design for compatibility with the IRWIN® Impact Performance Series™ Magnetic Screw-Hold Attachment.Specifications:Tip: Hex 4mm.Length: 25mm.Pack quantity: 2.