The system has two parts: the transmitter and the receiver. The transmitter plugs into an electrical outlet, and the wireless dog collar has the receiver. The transmitter sends out a radius of radio frequencies, and you can adjust the signal distance to your desired boundary space. If your dog goes beyond the perimeter you set, she’ll receive an electric shock. The static shock is not painful or traumatic – it’s similar to a splash of cold water in the face. Some shock collars, however, cause slight skin irritation. The Humane Society encourages owners to clean their dog’s neck and contact points regularly and not leave the shock collar on for extended periods of time.