3M Aluminum Oxide Sandpaper is used for general purpose sanding on paint, wood and metal. Be sure to sand with the grain of the wood and always work through a sequence of grits, from coarse to very fine. This sandpaper is made with aluminum oxide mineral.3M Aluminum Oxide Sandpaper 9003NA, 9 in x 11 in, Coarse grit. This coarse grit aluminum oxide sandpaper is used for general purpose sanding on paint, wood and metal. Use it by hand, on a sanding block, or cut it to size for a power tool sander. Be sure to sand with the grain of the wood and always work through a sequence of grits, from coarse to very fine. Also available in flexible sanding sponges for flat and contoured surfaces like raised panel doors, cabinets or windows. Choose a block sanding sponge or for hard to reach areas, like corners; try one of the angle sanding sponges.