These 3M 9-inch-by-11-inch sandpaper sheets easily remove rust, paint and other substances. This product provides general purpose sanding for many materials, including wood, metal, plastic, fiberglass and painted surfaces. The aluminum oxide lightweight paper is ideal for both woodworking and metal working. Each sheet measures 9-inches-by-11-inches. There are 25 sheets included in the package.It uses Aluminum oxide grit sandpaper.