Each set of 4 clear plastic grids measures 11" x 11" and interlock to form an 22" x 22" worksurface. Use as an easy to clean cutting surface and turn upside down for a smooth drawing surface that can also be back lit. Creator's stained glass tools and Morton System tools all plug into this grid surface. You can expand the grid surface to any size table by purchasing additional sets. 4 grids per pack.