Wireless Electric Dog Fence Pet Shock Boundary Containment System Electric Training Collar For Small Medium Large DogsThis 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