I echo the previous review about getting the right size. I purchased the large thinking, bigger would be better, but the large is REALLY large. Would probably work well for attaching to a kayak, but pretty big to use on foot and bike. I also don't really like the zip-lock type closer, which is tough to use if you are taking the maps out often for closer review. Used for adventure racing and didn't get it closed all the way a couple times and got water in it.