This is a genuine Ryobi replacement part, it is sold individually. The platen is the part of the sander that you attach the hook and loop sandpaper to. To prolong the life of the platen try not to put to much pressure on the sander when sanding. Excessive pressure creates heat build up in the sanding pad which will quickly damage or even melt the tiny plastic hooks on the pad. Compatible With: - CFS1503K Corner Cat Sander - CFS1503 Sander - CFS1503G Corner Cat Sander