These are great!
So after not knowing which size to buy, I finally opted for the 20L and it was much larger than I was expecting. Plenty of room for clothes, towel, food, whatever you would need for a day or maybe even a light over night packing. You won't fit a sleeping bag in there, but clothes and other personal items would fit no problem. I also have a 10L bag which is great for smaller items, food, or a few clothes. I haven't tried to stuff it, but it's great for a day trip. I haven't submerged these under water, but they have gotten wet on the outside and everything inside remained completely dry. I like having the see-thru window too. It's foggy, but easy enough to see what's in there. Great bag for the price.. I wouldn't hesitate to buy more of these.