While most screwdriving bits are simply compatible with impact drills and drivers, IRWIN® Impact Performance Series™ fastener drive bits are engineered for maximum durability and long life with impact drivers. These bits are forged* rather than milled, so they fit fasteners more precisely, which reduces stripping and increases the life of the bit itself - IRWIN's Impact Performance Series bits have three times longer life than traditional bits. Manufactured with heavy-duty, cold-forged, high-grade steel, they'll withstand extremely high torque output. Plus, a black oxide finish resists corrosion and increases the life of the bit.