This Round, Flexible, Plastic/Foam Backer Pad is designed for use with 5 inch polishers. The Pad is ideal for use as a back support for resin-diamond discs and is held in place securely with a 5/8-11 hub that attaches directly to your grinder/polisher. It cleans easily with soap and water or a mild solvent. This backer pad is for use with grinding and polishing wheels which attach using a hook/loop system.