Great portable water bowl
This is a great portable water bowl. I purchased the Medium and it is more than enough water for my 60ish pound lab/pit mix. Holds water extremely well, lightweight and portable.
If I had to give one critique it would be when you're out with a limited water supply. If you were out with only one or two dogs you'd be using a lot of water to fill up the bowl. If you had to pack up (on a hike or something similar) and move you'd need another way to store that water for reuse later or you would have to dump it out, essentially wasting your limited supply.
I'm not going to dock it a star however. Even with the medium size and a small amount of water, I can get the bowl to maintain it's rigidity long enough for my dog to drink.