These backup pads enable the use of standard 9-inch hook and loop abrasive discs with the Porter Cable 7800 Drywall Sander. The foam pad, backed with velcro, attaches securely to the PC 7800 using the stock nut. Each durable backup pad lasts through multiple sanding discs, allowing for easy swapping and reattachment without loss of adhesion. This hook-and-loop system can increase the lifespan of your abrasive discs by allowing them to be removed and reattached multiple times. Compatible with a variety of 9-inch sanding systems, these backup pads offer a convenient solution for your drywall sanding needs.