"I bought the first one for my puppy. He is now 20lbs and just outgrew it so I bought a medium, I love this thing. I can throw him in anytime he is too tired on a hike. The dog is high on your back so they can look over either shoulder. They are much more secure in this than in front with their legs hanging. It is also easier on me to do normal things with him on my back than hanging in front (try to tie your shoe with a dog on your belly) Everywhere I go with him in it everyone asks me where I got it. My dog loves it. "

"Great dog carrier. My dog is 29 lbs and fits great in this backpack. I got this for one of my dogs because he has bad back legs and he gets tired if we go for any long walks, but gets more upset if he cant go. We have a few strollers as well, but I like this because is light weight and easier to carry then the stroller. It looks well made, I am very happy with this purchase so far. The husband likes it as well, (since he takes him everywhere). He was ok getting him in the first time (we gave him his favorite dog cookies, so he has one in his mouth in the pic lol and he seemed very comfortable. I would recommend!"