The Wheeler 72 Piece screwdriver set features 54 hollow-ground flat bits, 4 phillips, 3 torx, and 8 specialty bits all made from durable S2 tool steel with a 56-58 Rockwell "C" hardness rating. The precision-engineered bits have a concave shape that allows for insertion all the way into the screw slot of rmaximum contact to prevent burred, buggered, busted up screw slots. The kit also includes 2 non-slip, overmolded plastic handles that come in a convenient hinged storage case whcih includes a bit location guide.