2.8 Joules of stored energy. Powers up to 35km of multi-wire fencing. Built-in battery save features to extend the life of your battery. Easy to use 5 stage rotary dial to change energizer operating functions. Uses 12V deep cycle rechargeable battery eg. marine type (battery not included). Ready to use Gallagher solar panels to conveniently charge the battery (not included). Bar graph can be used to indicate battery capacity and output voltage.