Great for Dungeons & Dragons, Pathfinder, and other combat miniature or role-playing games;Double-sided Dry-Erase Surface with interlocking positions on each side;Both sizes of tiles have 1 grids and are fully compatible with each other. Use 10 tiles for large rooms and areas. Use 5 tiles for smaller rooms and corridors.;Constructed of strong chipboard approx. 1/8 (3.8mm) thick. This combo set weighs about 3 pounds.