These collars have worked out perfectly. I use one on my dog that like to bark and charge anyone walking in front of our house. When we are out hiking and I want to let them off-leash if they are wearing these collars they respond immediately just to a beep. In fact my dogs have responded so well to the beep I don't even use the prongs. I've never had to vibrate or zap them. I would recommend this product for anyone who has more than one dog.