I have just purchased a second one of these (jumbo model) from Amazon; I've owned another one for 10 years. These are really well made, bullet proof bags that will keep all your stuff dry unless you submerge the entire bag in water.

These bags don't have a stiff shape, so you can load them with tons of stuff. The seams are all completely watertight, and the only way water can get in is through the top zipper, which is protected by a large Velcro flap that covers the zipper, so even in driving rain, it stays dry inside. I have looked out the window of an airplane and seen my bag sitting in the rain on the tarmac, and I know my clothes will be dry when I get to the luggage carousel.

There are no dividers, no pockets, no key loops of other gadgets inside; just a giant canyon of dry storage. The bottom isn't stiff either, so when you lift from the supplied shoulder strap, the bag will tend to fold or bend a little in the middle. I usually carry the bag with the handles so it's not an issue. I have loaded it with over 50# of stuff without a problem. It will carry heavy clothes, boots, camping gear etc.

After 10 years of use in airports, buses and boats, my old bag is still going strong. Highly recommended.