The Parmak Mag 12 Fence Energizer is best suited for small to medium-sized fences and enclosures. The Energizer is a low impedance fence charger with a built-in performance meter that indicates the exact condition of your fence. The Parmak Mag 12 Fence Energizer has no moving parts which ensures years of dependable, trouble-free operation. Get up to three months of continuous operation between battery charges. Weatherproof.