Each full box of Role 4 Initiative Dungeon Tiles contains about 900 square inches of double-sided battle grid tiles that interlock like puzzle pieces. Compatible with both dry-erase and wet-erase markers. Allows the game master to pre-draw all their maps before the start of the game, and then only reveal the tiles one at a time to maintain the Fog of War. More flexible than a traditional game map, you can easily hide traps on the reverse side of the tiles and make the players go exploring to figure out the map's layout.