ProMariner ProIsoCharge Battery Isolator 120Amp 1-Alt 2-Bat - 12V 23121. 23121 System Volts DC 12 Max DC Amps 120 Amp Alternator Input1 Battery Outputs 2 Size 5.35"(l) x 5.875"(w) x 3.125"(h) Weight2 lbs Significantly Smarter... ProIsoCharge delivers...