The Irwin Tools 1840314 14-Piece Impact Series Drive Guide Set is part of the new line of Fastener Drive bits designed for use in impact drivers. While most screw driving bits are simply compatible with impact drills and drivers, Irwin"s 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 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. The14 piece set includes a 2.25-Inch long magnetic insert bit holder with C-Ring, a Compact Magnetic Screw Guide and 12 1-Inch insert bits, 6 Phillips and 6 Square Recess.