Electric Dog Fence System Pet Tone ShockOur Petluv fencing system is a reliable, cost efficient pet containment system. A buried wire transmits a harmless radio signal. When your dog approaches the boundary, the signal causes the dog's collar receiver to deliver a warning beep first. If your dog continues closer to the boundary, the system will issue a mild shock. If your dog continues further, the system will issue stronger shocks until your dog returns to within the boundary you have set