Heavy Duty 5 inch abrasive disc made from semi open web that contains extra course silicon carbide through the entire thickness of the disc. Outlasts most other discs. Discs are 5/8 inch thick. For use with Aargo Tools part # 572028, 5 inch back up pad and Aargo Tools part # 904058 5 inch Air powered Sander or part # 904060, 5 inch Electric Sander which can be ordered separately.