SurfPrep 5 Backup Pad PSA'4250000 SurfPrep Backup Pads come in a variety of options depending on the products you are using as well as the surface youre sanding. Hook & Loop Backup Pads are made with smaller hooks which are excellent for the quick release of SurfPrep Foam abrasives. J Hook Backup Pads have a longer hook design that works well with SurfPrep Pad Savers, Interface Pads, Film, Paper, & Non Woven Discs Pads. PSA are meant to be used with Pressure Sensitive