... Abrasive Disc. 2). Grit: 16#---400#. 3). Diameter:4", 4.5", 5", 7", 9" 4)Backing: Velcro. Velcro Sanding Disc (Suitable for Grinding ... and Polishing for Automobile)Material: Aluminum oxide, black silicon carbide, ... rate and smooth polishing surface . Applications: Mainly grinding and polishing for automobile, paint, wood, stone, metal and ...