This Gallagher M1100 energizer charger powers up to 110 miles / 650 acres of clean fence. Crafted from a rugged combination of tough, high impact plastic for its outer casing and a built in lightning diverter with the latest internal circuitry - this energizer is designed to last. The M1100 replaces Gallagher's trusted M1000 model with more power. The added power reserve in this unit has built-in technology that increases voltage output when fence conditions change. Reliable and powerful, this energizer is best suited for large pastures.