I bought this dog backpack for our approximately 40 pound Border Collie. It fits him super well and has a small storage capacity. I was able to fit a waterbottle for him in one side of it and other stuff in the other side. It is water resistant, but after prolonged exposure it does begin to seep into the insides. I love that it has a handle on it, our dog decided to slide down a mountain, so it made it easy to grab him when he got close enough coming back up and pull him to full safety.