The Automatic 140 Amp Dual Battery Isolator is all you need to charge Two Battery . Voltage Sensitive Relay cuts in at 13.3 volts and cuts out at 12.8 volts to your primary battery is always and to start your vehicle. It's like having two separate power sources for each battery while only having one alternator! Unlike other isolators on the market, the Automatic 140 Amp Dual Battery Isolator is IP67 Certified. This International Protection rating means that your isolator is safe for use even for your off-road needs in dusty, wet and unexpected extreme weather environments. Great for extreme vibration applications as well. This battery isolator suitable for 12V 140 Amp, Truck, SUV, RV, ATV, UTV, Boat and so on. Forget the diode relays and so-called "solid state" devices that can you of 2 amps of output power! The Dual Battery Isolator is the unit designed with programming to deliver performance - with ZERO sacrifice. This battery isolator built ultra-small to fit anywhere! A under the hood to to your dual batteries. Cause your accessories to run from a separate battery while the engine is not working on your vehicle, and at the mean time holding your main battery and your vehicle always to work. Continuous Rating: DC 125A Intermittent Rating: DC 140A Power Consumption: 10mA (Standby)/ 330mA() / 0mA (Storage) Terminal Studs: M6(1/4inch) colour: black Material: ABS Size: 6.5cm x 6.5cm x 5cm Package Contents: 1 x 140 AMP Battery Isolator 1 x Blue Ring Terminal 4 x Screw 1 x English manual Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.