The Octopus is a portable or shelf type charger with (10), 12 volt, 6 amp independent circuits. Batteries in different states of discharge can be connected, and each will receive the proper charge. No over or under charging. The Green LED blinks indicating full charge. The batteries can be left connected indefinitely with only an occasional check of water level. Model QPIE12v/6Ax10 is perfect for gel's and wet starting type batteries. Model QPAGM12v/6Ax10 is a three stage charger for AGM type batteries. Tri-color LED's indicate what stage each battery is in. The Octopus is polarity protected, and there is no sparking if the charge leads come together. In addition, more than one set of leads can be connected to any battery to increase the rate of charge in 6 amp increments.