IRWIN Tools Impact Performance Series Insert Bit Set, Assorted Hex, 1-Inch Length, 8-Pack (1902388) Built for maximum durability and long life with impact drivers Precision tip geometry delivers superior fitment, reducing stripping and cam-out Manufactured with heavy-duty, cold-forged, high-grade steel to withstand high torque output Black oxide finish resists corrosion and increases life of bit 1/4" quick-change shank is designed to work with impact drivers, and reduces slipping in standard drill chucks