6-in-1 Device: Combines a powerful battery charger, engine starter, maintainer, battery and alternator tester, desulfator 100A engine start, 30A boost mode, and 6A Battery and alternator testers let you diagnose battery and electrical issues Fully automatic operation that employs an advanced multi-stage charging algorithm Bad battery indicator Desulfation mode Reverse hook-up protection prevents damage to the charger, vehicle, and battery if the connections are reversed Float mode monitoring adds a charge as needed to maintain a fully charged battery Auto voltage detection automatically detects the voltage of a connected battery