Aluminum oxide steel resin fiber disc with 7/8 in (22.23 mm) arbor, 13,300 max rpm, 3 pack. Ideal for weld grinding, grinding, blending, finishing, deburring and other general purpose applications. Can be used on most types of steel, as well as fiberglass and plastics. Constructed with a heavy vulcanized fiber back, coated with abrasive grains and bonded together with a tough, heat-resistant resin for fast cutting action and long life. For use on right angle grinders.