The PetSafe Rechargeable Waterproof Bark Control collar uses several features designed to shorten the training phase and promote good behaviour. The bark control collar has a unique sensor that provides the most reliable bark detection available. The system has 15 levels of static stimulation. It begins with low-level stimulations. If excessive barking continues, the stimulation intensity will increase with each successive bark until the barking stops. Once the dog has learned to reduce the barking, the initial warning stimulations are reduced.