This waterproof compression dry bag is the very best way to transport gear for kayak camping that I've run across yet. I've tried MANY different ways to keep the volume down, and run into the same issues every time. Vacuum sealed bags work great - for the trip out. However, once you release the seal to access your items there is no way to re-seal. I've tried the roll up bags with limited success - they aren't really completely waterproof. Standard dry bags are good for day trips, but when you need to maximize storage they hold too much ir when you attempt to compress them small. This bag allows trapped air to escape through the one way valve, and has four way straps to further compress items.