I just love this brace. I have a 14 year old dog whose knee was buckling under her due to looseness around her rear stifle joint. We go for off leash hikes on wooded trails and she is a very active dog. I did not want her to tear her ACL so I bought this brace. I bought the medium size for my 38 lb dog. It fits her perfectly and doesn’t slow her down at all. I attach it to a mesh harness rather than her collar, since I am afraid that she could hurt her neck if she gets too rambunctious while playing with other dogs. I shortened the two Y arms of the harness by 2” so it all fits beautifully. I have washed it twice already (remove the 2 metal stays first), and it looks as good as new each time. Best of all, my vet told me her joint is feeling stronger already and I only use it on her when we go for our hikes. I have given the name of this company to a lot of people who ask me where I bought it when they see my dog running around with it on. I am submitting a video. Well worth the money.