Bussmann (RB/BI-70A 70 Amp Battery Isolator Battery isolators prevent auxiliary batteries from draining main battery power in vehicle electrical systems, ensuring reliable starting power is available when you need it Solid-state technology isolates each battery circuit to extend battery life by allowing each to charge and discharge according to need 70 Amp kit includes wiring and hardware for basic installation - an optional installation kit is available separately for advanced installation Easy to install kit connects alternator to one main and one auxiliary battery - ideal for use in light trucks, RVs, and select commercial and marine applications Designed by Sure Power, the leader in battery isolators, for superior performance that exceeds original equipment manufacturer specifications