3M™ Purple Clean Sanding Disc 334U with 3M™ Hookit™ Attachment System features a precise hole design for improved life and dust extraction. This disc offers the coarsest grade available for fine featheredging and the final sanding step before priming. The multi-hole disc pattern lasts 2-3 times longer than our traditional no-hole, 5-hole or 6-hole discs. It is designed for quicker changes because hole alignment is not required. Use with the suggested 3M™ Backup Pad PN20427 and PN05771.