Irwin 1840315 Impact Performance Series™ 33-Piece Fastener Drive SetWhile 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.