This charger has it all with 6 and 12 Volt capabilities, 2 or 4 Amp charge rates. The BikeMaster intelligent charger / maintainer is ideal for charging / maintaining 6 and 12 Volt lead acid batteries, including conventional acid batteries (Wet), factory-activated, maintenance-free batteries (FA), absorbed glass mat maintenance-free batteries (AGM) and gel batteries (Gel Electrolyte). This fully automatic battery charger detects 6 or 12 Volt, reverse polarity, overcharge and short circuit protection in addition to testing if the battery is good or bad. It has easy-to-read LED lights that indicate power on, 6 or 12 Volt selection, 2 Amp or 4 Amp charge rates and the status of the battery charge. This charger/maintainer comes with a five-year warranty.