I bought the large for our 80lb dogs, and we ended up ordering 2 more for xtra large that would fit a deep chested dog. I used one for about 5 days straight as we took our Labrador to the lake home and she swam for about 3 hours a day and did not mind the jacket whatsoever. It was great to have two strong handles on the top to control her when we were fishing, as she get's frantic trying to get to the fish. We also liked the neoprene material that goes under the dog and has great large Velcro attachments that do not cause any issues. It also has two quick release buckles under the belly and chest and another around neck, but behind the foam cushion covered by nylon and this helps the dog keep its head up higher than swimming without the jacket. This helps her not swallow as much water too. Great design over all and the top part is highly reflective so easy for her to bee seen swimming in the cove and boaters can also see her much easier. Thanks for letting us share our experience.