Most double-ended screwdriving bits require a bit holder for use with impact tools, but IRWIN Impact Performance Series double-ended power bits feature DoubleLok technology so both ends of the bit lock securely into impact drivers and quick-change chucks. In fact, they're engineered for maximum durability and long life with impact tools. These bits combine two bit tips in a durable one-piece design for added convenience and extended life, and each end of the bit has a 1/4" quick-change shank that fits directly into an impact driver - a feature only available with IRWIN bits. The bits are designed with precision tip geometry so they fit fasteners more precisely, which reduces stripping and cam-out. They're manufactured with heavy-duty, cold-forged, high-grade steel to withstand high torque output, and a black oxide finish that resists corrosion and increases the life of the bit. Plus, they also have a unique Power Groove design for use with the exclusive IRWIN Magnetic Collar Attachment, which prevents fasteners from slipping and wobbling.