2-Pack Norton Backup Pads - Enables use of standard 9" hook and loop abrasive discs with Porter Cable 7800 Drywall Sander Foam pad backed with velcro attaches to the PC 7800 with the stock nut Each backup pad lasts through multiple 9-inch sanding discs Easy swapping of sanding discs with the hook & loop backing Save substantial money over buying Porter Cable abrasive sanding pads 2-Pack Norton Backup Pad For PC 7800 (Replaces SPBP) Norton back-up pad is for use with the Porter-Cable model #7800 drywall sander and Norton hook & loop sanding discs. Using the hook & loop system is more economical and effective than using the stock pads with glued abrasive. Use several sheets of sanding discs without having to replace the foam back-up pad each time. Easy attach sheets with Hook & Loop Foam pad attaches to sander with the stock nut Far more economical than stock discs