Assortment Kit Alpha PVA Quick Change Polishing Pads 5 Pack Quick Change Backer Pad sold separately This Quick Change process saves time & increases productivity. Polish marble or travertine without using water or messy chemicals. The aluminum backer plate is attached to the polishing tool and each of the pads has a snail lock adapter. The adapter simply fits into place and locks on with a twisting motion.To remove the pads simply untwist and remove, then replace with the next grit.