A signal is sent by the transmitter to a receiver located on your dog's collar. The signal is transmitted through a wire which is placed along the boundaries you want to establish. The wire is really an antenna that carries the signal. The receiver, attached to your dog's collar, provides a warning beep when he approaches the wire. If he starts to cross the wire, he will receive a mild correction. Although harmless, this will dissuade him from continuing further. This system features a convenient rechargable battery plus all the features of the Standard Radio Fence. Covers up to 25 acres and includes one receiver and a manual.