Featuring the latest state-of-the-art solar panel with superior charging power the Magnum 12 Solar-Pak eliminates battery recharging, thereby saving you time and money. The sun`s energy charges the fencer by day and a sealed 12 volt rechargeable battery powers the fencer at night. Battery included. Built-in performance meter tells the exact condition of the Range: 30 Miles. Joules Low: 1.1. Joules High 3.1+.