From publishers' website:
Delve the deepest, oldest tombs and catacombs with Flip-Mat: Ancient Dungeon, a gorgeous double-sided battle-scale map of two complete dungeon levels! Both sides show numerous rooms and corridors that YOU populate with your own ancient treasures and terrors!
This portable, affordable map measures 24" x 30" unfolded, and 8" x 10" folded. Its coated surface can handle any dry erase, wet erase, or even permanent marker. Usable by experienced GMs and novices alike, GameMastery Flip-Mats fit perfectly into any Game Master's arsenal!