Diablo 4-1/2-In. 36 Grit Aluminum Oxide Fiber Discs, 4-Pack, are ideal for extra heavy stock removal. These discs are made from a premium aluminum oxide blend to allow fast material removal and long sanding life. Keep your sanding discs longer with Clog-SHIELD which reduces pitch build-up and clogging, and ENDURA-BOND, a grit-to-backing bond that provides durability. They are for use for wood, fiberglass, and plastics.