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.