Gator 3-Pack 4.5" x 7/8" 36 Grit Aluminum Oxide Fiber Discs are designed to be used on angle grinders with a backer pad for aggressive sanding of metal, fiberglass & painted surfaces. They are resin bonded to resist heat & humidity for longer life. Gator Red resin fiber discs are designed for use on right-angle grinders, using a 7 inch backing pad to grind wood, metal, fiberglass and painted surfaces. The high-quality abrasives along with the speed of the machine make Gator fiber discs ideal fast stock removal, shaping, blending and leveling.