Proxxon Fiber Reinforced Synthetic Resin Bonded Aluminum-Oxide Cut-Off Wheels are intended for cutting metal, nonferrous metal, alloys, and stainless steel. Cut-off wheels can also be used on wood, plastics, and some softer stones. Nearly unbreakable, making it usable to remove stock. Please Note: Cut-off wheels are designed for cutting on their outside edge only. Do not use the face of the wheel for grinding.