When your dog wears the special collar receiver, and when you set the range by the transmitter, the transmitter will send a radio signal that the receiver can receive.

Your dog will emit a Beep Sound Warning when they approach the preset distance you decide on. As long as your dog continues to approach the preset invisible boundary and passes across the distance you set, the Beep Sound Warning/ Vibration/ Shock mode will be activated. This encourages your dog to return to the safety zone of your yard.