I bought this harness system for both my dogs, a stocky Jack Russell Terrier and a little Yorkie/Chihuahua mix. Both are hard to fit...the Jack is extremely muscular, and the Chorkie is tiny, but pulls like a freight train. They've always been hard to fit so it's a real treat to have a custom harness for each of them. The PF harnesses are well-made and easy to put on. My dogs are safe and comfortable (and handsome!) in them. Walks are much more fun now. My only complaint is that it took forever to pick the correct pieces based entirely on the breed sizing chart, which is a bit vague. It would be really helpful if the website also included pictures of each harness piece laid out by a yardstick. Extremely happy with this purchase!