Abrasives: aluminium oxide, silicon carbide, alumina zirconia Backing: Fiberglass, fiber, nylon, ABS, plastic, metal Application: deburring, removing welding seams and spots, removing scale, rust and oxidation of any kind, blunting sharp corners and edgesAvailable size: 4", 4.5", 5", 6", 7"Both flat and conical type are available flap disc