This Craftsman(R) drive bit set is made of S2-modified steel for an unmatched durability. Resistant enough to be used with an impact driver, they benefit from an optimized torsion zone. The CNC-machined bit tips ensure a precise fit in screw heads, therefore reducing risks of cam-out. The set includes 7 bits of 1", 13 bits of 2", 2 bits of 3 1/2", 3 nut drivers, and 1 magnetic bit holder of 3". This product comes with a plastic carrying case and is compatible with the Versatrack(TM) portable storage system.