Full Circle Level 360 Sanding Discs for Radius 360 & Porter Cable 7800 Drywall Sander with PowerPad (25 Pack) are made of aluminum oxide paper which is clog resistant and self-sharpening for longer life. Loop backed sandpaper firmly attaches to the foam disc, preventing debris from collecting behind the sandpaper, and eliminating a major cause of streaking. Level 360 discs are available in 7 grits for all your needs.