The BatteryMINDer Solar Charging System is an ideal choice for 12 Volt battery operations. This complete system is specifically designed for charging and maintaining up to four 12V batteries of any size/type/brand. Extends performance and life of 12V lead-acid, maintenance-free, marine deep cycle and sealed AGM batteries. Fully automatic desulfator dissolves life-shortening sulfate using safe low voltage high frequency pulses. Purchasing this unit qualifies for a Free Digital Multi-Volt Meter (DMVM) (valued at $24.48) when you register your warranty at www.BatteryMINDers.com.