Flexible Backer Pads for Contours and Inside Curves Alpha® Flexible Backer Pads provide the flexibility needed for polishing tough contours, inside curves, tight corners, and other shaped surfaces. Their flexible construction allows the pad to conform to the work surface while supporting polishing and finishing accessories. Hook and Loop Backing for Polishing Accessories The hook and loop backing accepts compatible polishing pads, sandpaper, and felt wheels, allowing the backer pad to support multiple polishing and finishing applications. Alpha originally developed the pads as part of its wet polishing system for use by fabricators, tile contractors, monumentalists, and restoration workers. 5/8"-11 Thread for Popular Polishers and Grinders Both the 4" and 5" Flexible Backer Pads use a standard 5/8"-11 thread for compatibility with many commonly used polishers and grinders. Each pad is rated for a maximum speed of 6,000 RPM and is built to withstand regular use while maintaining flexibility.