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 conventional acid batteries, factory-activated, maintenance-free batteries, absorbed glass mat maintenance-free batteries (AGM) and gel batteries. 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 needs replacing. 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.