Cut-off wheel is reinforced with fiberglass for increased durability. For slicing and cutting metal including hardened steel. Cut-off wheels make it easy to cut bolts or screws or make slots in rusted or stripped bolts and screws for removal with a screwdriver. The cut-off wheel cuts only along its edge. Do not attempt to sand or cut curved holes with them. Ideal for cutting, grooving and trimming all kinds of metal. May also be used on other materials-including thin wood, plastics and ceramics.