The 3M™ Perfect-It™ Random Orbital Polisher Back-Up Pad helps keep compounding and polishing pads working at peak performance when used with 3M™ Perfect-It™ Random Orbital Polisher. Helps 3M™ Perfect-It™ Random Orbital Compounding and Polishing Pads stay firmly attached to the tool. Designed for use on 3M™ Perfect-It™ Random Orbital Polishers with 15 mm and 21 mm throws, firm-but-flexible pad.