Solar-powered, low impedance energizer controls 1-25 acres or 1-10 miles of fence wire. Recommended for small areas, horses, cattle and small animals. 0.15 joule output; 12 V internal battery (included). Feature high performance digital technology, rugged all-weather construction, internal lightning shield, big easy-grip knobs and heavy-duty, long life construction. T-post mounting hardware included.Only Power Wizard energizers feature state-of-the-art ultra low impedance technology to increase energy output to maintain consistent shock power on fence lines which have deteriorated or become heavily weeded. Feature high performance digital technology, rugged all-weather construction, internal lightning shield, big easy-grip knobs and heavy-duty, long life construction.