The Extra Hard Set, 43-piece, is a comprehensive Pick and Click set for all standard screwdriving tasks. It includes all the standard drill bits and sockets you need for screwing work. The screwdriver bits are made from heat-treated, S2-modified steel for hardness and wear resistance. They are color-coded to help you find the right bit more easily. The set is housed in a sturdy Pick and Click case, allowing you to assemble your own toolbox and keep your bits well organized and protected. All bits in the set have a 1/4-inch hex shank for use with three-jaw drill chucks and hex drill chucks.