IRWIN Tools 1902389 Impact Performance Series Screwdriver Power Bits, Assorted Hex, 2-Inch Length, 4-Piece Built for maximum durability and long life with impact drivers Precision tip geometry delivers superior fitment, reducing stripping and cam-out Power Groove designed for compatibility with IRWIN Impact Performance Series Magnetic Screw-Hold Attachment Manufactured with heavy-duty, cold-forged, high-grade steel to withstand high torque output 1/4" quick-change shank is designed to work with impact drivers, and reduces slipping in standard drill chucks