Universal drill bit with hex chuck by STHOR 21692 designed for professional use - drilling in hard and untreated materials: concrete, stainless and acid-resistant steel, aluminum, ceramics and wood Made of hardened steel with a hardness of 90-92 HRC, the tungsten carbide blades exhibit greater hardness and wear resistance The ¼" hexagonal HEX chuck allows attachment to cordless screwdrivers and impact wrenches.