My golden retriever puppy learned to ring the bells to go out after just 3 times of us showing him how. He loves to chew things (like most puppies) but leaves the bells alone. I guess he knows that it us his ticket outside. The black material is pretty thin and at first I wasn't real happy with my first impression. I guess since our puppy doesn't chew it or pull on it, it hasn't really been tested for durability. The bells ring loud enough and aren't over powering.