UNITED ABRASIVES - SAIT 50165 2A FIBER DISC 5"" X 7/8"" 60 GRIT ALUMINUM OXIDE ALUMINUM OXIDE GRAIN GENERAL PURPOSE. CLOSED COAT STRUCTURE FOR MORE MATERIAL REMOVAL AND BETTER FINISHING. RESIN OVER RESIN CONSTRUCTION FOR A STRONG BOND THAT IS RESISTANT TO HEAT AND MOISTURE. VULCANIZED FIBER BACKING FOR HEAVY DUTY SANDING.