Fully Automatic - Designed to maintain 12 volt batteries up to 250 amp hours Increase Performance - Precision regulated 13.4 VDC float modeCan be left on for extended periods without overcharging or damaging batteriesWill not drain battery if AC is removedLED status indicatorUser adjustable for gel'sBuilt-in Safety - Reverse polarity protected. Certified to U.L. 1236 Marine1 Year Warranty