This electric fencing system is a reliable and cost-efficient pet containment system. The transmitter emits a harmless radio signal in a radius around itself and the signal is detected by the collar. If your dog walks out of the signal boundary of the transmitter, the receiver will deliver warning beep sounds for 3 times and then start to emit safe static stimulation continuously for 3 minutes, pause for 1 minute and emit safe static stimulation for 3minutes alternately until the dog goes back into the signal boundary. Your dog will naturally seek to avoid correction, and is content staying within established boundaries. Keep safe in limited space.