This bark control collar has a unique sensor that provides the most reliable bark detection available. It also uses temperament learning to decrease and, in most cases, eliminate nuisance barking. 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. As a built-in safety feature, if your dog barks 15 times or more within a 1 minute 20 second period, the Bark Control collar will automatically shut off for 3 minutes. This Lite version of Bark Control is specifically designed for dogs with a sensitive or timid personality. The stimulation levels are very gentle even when increasing to higher levels. Lite bark collars can be used with dogs of all sizes, but they are particularly well-suited for small to medium sized dogs.