The Pettags No Bark Collar is an efficient method of behaviour control which causes no harm to your dog. The Anti-Bark Collar features two different modes which can be selected to work specifically for your dog, a sound mode and vibration mode. When dogs bark with the collar set to the sound mode, it emits a high pitched sound, which is inaudible to the human ear but is considered unpleasant for dogs. In the vibration mode, the collar releases a vibration which you can set to low, medium or high, each time your dog barks.The Anti-Bark collar is made from an adjustable nylon.Requires 3 x LR44 1.5V Batteries - included.Size: Small - suitable for dogs weighing 3.6 - 11kg