ZERO VOLTAGE DROP: 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 only unit designed with programming to deliver performance - with ZERO sacrifice. This battery isolator built ultra-small (2.6inch x 2.6inch x 2inch) to fit anywhere! A under the hood to to your dual batteries.VOLTAGE RELAY: The Automatic 140 Amp Dual Battery Isolator is all you need to charge Two Battery . Voltage 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!RUGGED DURABILITY: 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 .EASY-TO-USE: The 140 Amp Dual Battery Smart Isolator comes with mounting plate and hardware.colour:blackMaterial:ABSPackage Contents:1 x Smart Battery Isolator with Screw accessoriesOnly 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.