Mercer 9" x 11" Sandpaper Sheets feature premium aluminum oxide grain that is resin on resin bonded atop sturdy latex-backed paper. These sandpaper sheets resist loading, moisture and heat and are great for use on Drywall, Ferrous Metals, Fiberglass, Metal, Non-ferrous metal, Paint, Plastics, PVC, Steel, Wood. These all multi-purpose sheets are sharp, durable and flexible providing fast cuts, long life and a consistent finish. Extremely heavy duty D weight backing for low grits including 36, 40, 60 and 80 grit. Standard, flexible, light weight A paper backing for grits 100 and up.