Patriot, Fence Alert Low Voltage Warning Light, Light Flashes If Fence Voltage Is Too Low Or There Is A Loss Of Power, Can Be Seen Up To A Mile Away, Works With Low Impedance Energizers, Replaceable Lithium Battery Can Power Up To 5 Years On Standby Or 2 Weeks Continuous Flashing, For Use With Poliwire, Polirope, Braid, Politape & Steel/Aluminum Wire.