Forget the traditional diode relays and so-called "solid state" devices that can you of almost 2 amps of output power! The Dual Battery Isolator is the unit designed with programming to deliver performance - with ZERO sacrifice. This compact battery isolator built ultra-small (2.6 inch x 2.6 inch x 2 inch) to fit almost anywhere! A under the hood to get close to your dual batteries. 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 ready 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 IP65 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. 12V 140 Amp Dual Battery Smart Isolator Sensitive Relay Specially Deigned for ATV, UTV, Boats, RV's 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 to work. Product name: smart battery isolator Product voltage: 12V Product features: capacity, can switch 140 ampere current, flame-retardant shell, waterproof design Coil power: 3.4W Contact capacity: 1a 140A 14VDC Contact resistance: less than equal 50m Insulation resistance: equal 1,00M Ambient temperature: -40~+125 Service life: electrical 1*1000000 (times) size:68x68x53mm Material:ABS colour:Black Package Contents: 1 * Smart Battery Isolator 4 * Screw 1 * terminal 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.