Damn! No one seems to notice how incredibly hot the neoprene on these sleeves gets their butt and back. Now I'm sitting on one of them in the car while I write. My lower back sweats a bit and my buttocks are bigger. (My boxer shorts feel damp.) A leather seat with a cover is hotter than without. I can't comment on the water resistance yet as I haven't sat on it after swimming or sweated a lot. I assume it will. Other than that, it's a good case, especially for the current price of $23. If anyone can recommend another case that's cooler and waterproof at the same time, I'd appreciate it. Right now I'm thinking about buying a non-waterproof case to put on top.