1Supports charging two batteries. When your first battery is fully charged, the isolator kit will automatically start charging the second (auxiliary) battery. 2Designed with cutting edge programming to deliver optimum performance. When the voltage of the start battery drops the isolator disengages from charging the auxillary battery to isolates the start battery and eliminates the possibility of draining it, ensuring that you always have enough charge to start your engine. 3Able to withstand extreme weather environments and is also water resistant. It is safe for use even for your vehicled needs in dusty, wet and unexpected extreme weather environments. 4This compact battery isolator has the ultra?small design to fit almost every condition. Is a perfect fit under the hood to get close to your dual batteries. Suitable for Utv, 12VDC Marine, 4wd, caravan and solar applications. 5The 140 Amp dual battery smart isolator comes with mounting plate and hardware. Does not include installation wires. Convenient for operation and installation use.