Publisher's blurb: Gale Force Nine's Official DUNGEONS & DRAGONS Game Mats are high-quality single-sided vinyl surfaces that are ideal battle grids for staging encounters during your adventures! The mats lie flat for ease of play and are sold in a sturdy polycarbonate tube for easy storage and transport. The mats may be marked with WET-ERASE markers to temporarily alter terrain areas or make other notes about battlefield conditions during play. The Game Mats measure 20" x 30" and are marked with a 1" grid. The Dungeon Master's Mat Set contains TWO vinyl game mats to stage your own encounters and adventures. The first mat is a simple 1" grid of stone tiles, the basic dungeon environment. With this mat, a DM can mark walls, doors and other dungeon features using a wet-erase marker. This mat will be the staple battle grid for any indoor encounter. The other mat is a green grass field; ideal for staging outdoor confrontations. Like the other mats, a few quick marks from a wet-erase pen customizes the mat with whatever elements the encounter calls for; add a tree line, forest path or campsite. The Dungeon Master’s Mat Set is an indispensible tool for every DM! Gale Force Nine recommends the use of water-soluble marking pens, like those used with overhead projectors (wet-erase markers) with our game mats. Vinyl is a very porous material and any marks make by dry-erase or permanent markers will stain the mat.