So what do you do when you need to pack a bag, and keep it water tight? Well you could check out a submersible backpack. The Westwater Waterproof Backpack 4900 by Watershed is a category 5 fully submersible backpack. Which means you can sink this bag to at least more than twelve feet before you'd worry about the contents getting wet - though in this case the Watershed claims the Westwater bag is good for depths up to three-hundred feet. Their patented ZipDry closure fuses all seams with overlapping radio frequency welds, turning multiple fabric pieces into one single piece of material. The backpack itself is made of Kryptothane fabric with five times the abrasion resistance of PVC fabric. The end result is a truly durable, in fact near-indestructible knapsack that can hold up to whatever adventures you may want to undertake. It doesn't hurt either that the Westwater has a simple clean look that can match to nearly any style.