Material: Made of high quality chrome vanadium steel, Quantity: 8 pieces, 4x1/4’’, 2x3/8’’, 2x1/2’’ Suitable for all drive sockets, bit inserts, for direct drive via the drill chuck or using a 1/4" hex holder For all drills, cordless screwdrivers and hand screwdrivers etc. Ideal for quick tool changes in electric screwdrivers For a firm hold, the hex shank can also be clamped directly into a machine chuck The hex shank is inserted into drill, square to accommodate 1/4’’, 3/8’’ and 1/2" nuts