The cut-off wheel is reinforced with fiberglass for increased durability and used for cutting metal including hardened steel. Great for contractors and the home hobbyist. Fits Dremel Craftsman Chicago and more. Ideal for cutting, grooving and trimming all kinds of metal. May also be used on other materials-including thin wood, plastics and ceramics. Cut bolts or screws or make slots in rusted or stripped bolts and screws.