I bought this bag having used smaller bags by the same company and noting how good they were at keeping contents dry in an open water sports community. This 25ltr version is ideal for my purposes; keeping all contents dry and securely held on my back whilst transferring between vessels or to/from shore in all weathers. As has been commented upon by others, it's big enough to hold a substatial quantity of kit and it really does keep everything dry and dust free. Having been thrown into water whilst wearing it I can confirm it really is water-tight in practice, though you may not be so lucky if it was not fastened in accordance with the instructions provided. The external pockets are idea for holding small bottles or equipment, and the front web pouch has a good expansion capacity for holding items ready for easy access. Additional internal pocket(s) would be beneficial for segregating smaller items to ease their recovery, and it should be noted that the larger panels are constructed from a different material to the sides; in place of a tough smooth neoprene/plastic finish on the front and back, the sides have a more woven and thinner material feel. I have come to trust this bag, and as I cannot find anything better for the money or capability elsewhere, I have now bought one for my partner to use too.