Irwin Tools 1840313 Impact Drive Guide Set with Accessories Built for maximum durability and long life when used with an impact driver Forged square and Phillips bits for superior fitment, reducing stripping and increasing bit life Manufactured with heavy-duty, cold-forged, high-grade steel to withstand high-torque output Black oxide finish on each impact driver resists corrosion and increases the life of each bit Power Groove designed for compatibility with IRWIN Impact Performance Series magnetic screw-hold attachments