The Forney 71664 5-Inch Aluminum Oxide Type 1 Steel Sanding And Grinding Discs are excellent quality aluminum oxide. Ideal for weld grinding, blending, finishing, deburring and other general purpose applications. Can be used on most types of steel as well as fiberglass and plastics. Uses a special heat treated (ceramic coated) aluminum oxide grain for fast cutting action and long life. Forney Industries is one of America's longest operating family-owned metal working product companies. Founded in 1932, Forney offers more than 5, 000 products for the hardware, automotive, farm & ranch and do-it-yourself markets.