The Extra Hard and CYL-3 Set, 35-piece, is a comprehensive Pick and Click set for all standard screwdriving tasks and drilling in concrete and natural stone. It includes all the standard accessories you need for screwing and effective drilling. 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. With the CYL-3 drills included in the set, you can drill into abrasive materials such as concrete and natural stone. The set is housed in a Pick and Click case, allowing you to assemble your own toolbox and keep your bits well organized. The screwdriver bits feature a 1/4" hex shank for use with three-jaw chuck drill drivers and hex drill chucks. The drills have a cylindrical shank that is compatible with three-jaw drill chucks.