This high output, portable starter/charger has both manual operation and fully automatic. Ideal for professional mechanics and do-it-yourselfers. For use with 6 and 12-volt batteries. It has a 15-amp fast charge to help charge a battery in 2 to 4 hours and the 2-amp trickle charge can charge a small 12-volt battery in 2 to 12 hours. Also includes 125-amp engine start for emergency engine starting. 2 LED lights signal fully charged and reverse hookup. The 6 function rotary switch allows you to select the appropriate function. The fully automatic function will not overcharge batteries.