3M Abrasive Disc Back-up Pad makes it easy to attach and remove 5" 3M Adhesive Backed Sanding Discs (sold separately) during the auto body sanding process. Pads work as part of the 3M Stikit system for easy disc changes and reuse, optimizing disc life. Firm yet resilient back-up pads make for smooth, even sanding of metal, fiberglass and other auto repair substrates.