For 6 and 12 volt lead-acid batteries. Automatic battery charger with reverse-polarity protection. Keeps batteries at full charge using float-mode monitoring. Most starter, deep cycle and gel type batteries can be charged and maintained. Automatically switches from full charge to float-mode monitoring as needed. For maintaining small and large batteries kept in storage. LEDs indicate: amber light indicates battery being charged, green light indicates battery is fully charged, and the red light indicates trouble. This battery charger has no power on/off switch. Plug into AC receptacle only after battery connections are made.