Forney 71657 Aluminum Oxide Sanding Discs  with 7/8-Inch Arbor, 7-Inch, 120-Grit, 3-Pack Excellent quality aluminum oxide steel sanding and grinding disc Ideal for weld grinding, blending, finishing, deburring and other general purpose applications Can be used on most types steel as well as fiberglass and plastics Uses a special heat treated ceramic coated aluminum oxide grain for cutting action and long life Type 1 sanding discs