IRWIN Tools 1892027 Impact Performance Series Double-Ended Screwdriver Power Bit with 4-Inch Length Built for maximum durability and long life with impact drivers. DoubleLokTechnology ensures both ends of bit lock securely 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 1/4" quick-change shank is designed to work with impact drivers, and reduces slipping in standard drill chucks