The JVA MB3 Mains/Battery Electric Fence Energizer can be powered from 240Vac mains, or a 12V battery. The JVA MB3 is suitable for small to moderate permanent electric fences. At 3.0 Joules (peak output energy) it is powerful enough to power up to 30km* of fence. Features: 3 Joules powers up to 30km fence.* LED Energizer and fence status indicator Large easy to use fence terminals O-Ring sealed enclosure for ant and moisture protection Lightning protection Easy to mount on wall with 2 screws Approved to Australian Safety Standards UV stable enclosure Comes with a plug pack for use on mains, and alligator clips for use on a 12V battery. Note the battery is not included. * The actual acres or kilometers of fence powered by this Energizer depends on your farm fence conditions and therefore varies greatly. The best method to compare Energizers is to use pulse output energy (Joules) **For connection from the Energizer live terminal to the fence you will need a suitable high voltage cable (not included).