From the website: Not only do these tiles provide a more realistic stone floor appearance, they are accented with various dungeon floor features that include broken stones, moss, water, blood, and dirt that add character to your dungeon maps. R4I has taken the realistic visual effects even further by implementing a "hidden grid" by rendering a floor of varied size and shape stone tiles, yet still leaving a subtle representation of the traditional 1" grid. Compatible with both dry-erase and wet-erase markers. More flexible than a traditional battle mat, start your game with a single tile and connect the tiles as the adventurers explore new areas. Never again give away clues as to which way the corridors may lead due to starting placement on a large mat. The interlocking tile modularity allows the Dungeon Master to draw many details of an area at his seat and then simply hand the tile to the nearest player to connect. Take advantage of the double-side feature by pre-drawing map features before the game and only revealing tiles as they are encountered. You can draw one side as it appears naturally, and the other side that shows all the hidden traps and magic features when they are triggered.