Sandpaper is a type of abrasive material used to smooth, shape, or clean surfaces by rubbing it against them. It consists of a sheet of paper or fabric coated with gritty particles like aluminum oxide or silicon carbide. These abrasive grains wear away unwanted material such as wood, metal, or paint. Sandpaper comes in different grit sizes, ranging from coarse (for heavy removal) to fine (for smooth finishing). It is commonly used in woodworking, metalworking, and automotive refinishing.