The MILWAUKEE Hook & Loop attachment method of this 5 Backing Plate means that any Hook & Loop enabled polishing pad can be used with the backing plate, giving you a greater level of freedom in selecting your accessories. The Milwaukee 5 Backing Plate is designed for use with MILWAUKEE M18 FUEL 15mm Random Orbital Polisher, but it has also been optimized for use with the MILWAUKEE M18 FUEL 21mm Random Orbital Polisher. The 5 Backing Plate can be interchanged between the two polishers as needed based on application requirements. The durable rubber design aids in the dispersion of heat in application which prolongs the life of the backing plate itself, saving you both time and money.