The Transpaw Gear Happy Harness is easily the most dog friendly dog harness Summit and I have ever used. Summit is an Australian Shepherd and weights about 70 lbs, he easily and comfortable fits in a size large. I have used many different dog walking harnesses and dog training harnesses from the time Summit was a puppy until recently when I discovered the Happy Harness. Summit was never really comfortable in any dog walking harnesses and always preferred a basic collar and leash. Now, we go on walks, hikes and even catches frisbees in the happy harness. It truly is the most comfortable dog harness ever made! Thank you TransPaw Gear!