Deltran's advanced SuperSmart Battery Tender Battery Management System is light years ahead of any standard battery charger. It's the first fully automatic, constant-current battery charger designed to charge and/ or maintain up to 5 12 volt batteries simultaneously at 2 amps. (Note: Please allow 2-4 weeks for shipment of this unit). Safe, No Spark Charging! To avoid dangerous dead-short sparking, microchip circuitry will not activate output voltage until clips are correctly connected to battery.