Sandpaper and sandpaper are made of a sheet of cloth covered with numerous grains of abrasive material that are used to rough out and finish (sand) wooden surfaces (and other materials).
For sandpaper, the abrasive material is of mineral or synthetic origin (emery, corundum) while for sandpaper it is flint.
This is the tool used by the carpenter for the final and finest finishing of surfaces.
The abrasive power of the paper is organized according to a scale organized in grain numbers that are between 16 and 2500. The lowest number (16) indicates a paper with a coarse grain and high abrasive power that is used for roughing, while in the highest number (2500) the grain is fine and is used for smoothing and finishing.