The Extra Hard Set, 43 pcs contains all standard bits and nutsetters you need to get your screwdriving tasks done. The screwdriver bits are made from heat-treated S2 modified steel for hardness and resistance to wear. They are colour-coded so that you can pick out the bit you need easier. The set is housed in a robust Pick and Click case you can use to build your own toolbox and keep your bits well organised and protected.All bits in the set have 1/4” Hex shank for use with three-jaw drill driver chucks and hexagonal drill driver chucks