SandBlaster multilayer flap discs are layered onto a depressed-center fiberglass disc. As the abrasive flaps wear, new, sharp abrasive grain is constantly being exposed providing a constant finish through the life of the disc. Made with heavy-duty backing that is coated with extremely durable Cubitron mineral for aggressive removal, clean cut, and longer life of sheet. Can be used on metal, wood, and fiberglass. 4-1/2" x 7/8". 13,300 RPM. 5/8" arbor must be used with 3M Quick Loading Adapter (model No. 9675).