20 Inch Stick On PSA Multipurpose Sanding Disc. Heavy X weight Cloth sticky backing. High quality abrasive sandpaper material is bonded with a pressure sensitive adhesive that won't leave any sticky residue. All purpose aluminum Oxide cloth discs works well with wood, softwood, hardwood, plastic, solid surfaces, non ferrous metal (aluminum, titanium, etc.). Open coating reduces loading and provides a more even finish. Resin over resin bonding. Anti-static - reduces dust. Anti-clogging stearate - provides extra heat resistance while reducing loading. Dry applications only. Assembled in USA.