This innovative collar has three correction modes, each with six levels of stimulation, so you can fine-tune according to the unique needs of your dog. If you choose, correction levels can also be set to automatically increase after each subsequent bark. The Automatic Safety Shut-Off stops stimulation after 50 seconds. Patented Perfect Bark technology ensures that your dog’s bark is the only stimulus to trigger the correction. The durable, waterproof collar (fits up to 28″ neck) uses one 6-volt battery (included) and has a low-battery indicator.