Size measurements are deceiving.
Works well for keeping a map dry and close at hand. Case in built very well and works like it is supposed to, but be warned, he dimensions that are given are the exterior dimensions. I thought the small at 8x12in would be just barely smaller than a piece of notebook paper but it is significantly smaller. I would suggest going with a med. The small works but it gives you a very minimal amount of the map that you can see at one time. The interior dimensions are 6x10.5in for the small. The med will be 10x14.5 interior dimensions. A much better amount of map to have showing.