Stored energy of multi-wire permanent fence, maintains output voltage through heavy fence load. Indicator light flashes with every pulse. Low impedance. Features a tough outer casing with a simple plug and play installation. Ideal for controlling domesticated animals or pets around the yard. Covers 60 to 100 acres, or 11 to 30 miles. Stainless steel terminals. UL (Underwriter's Laboratories) listed. 2-year warranty.