Description: Premium quality: the voltage sensitive split charge relay is made of solid glass fiber reinforced nylon shell, which is sturdy and durable in use. It is not easy to aging and abrasion resistant, ensures maximum strength and durability for long lasting usage. Dual battery smart isolator: the dual battery isolator voltage sensitive relay is all you need to charge battery systems. Its dimensions fits heavy duty modular fuse box series and battery switch, which matches mainstream products in market. Easy installation: the 12 volt voltage sensitive relay with surface or panel mount options, which provides flexibility when installing. No voltage drops comparing to battery isolator diodes (0.6v). Combine / open voltage: dc 13.3v / 12.8v. Voltage sensitive relay: this automatic 140 amp dual battery isolator is all you need to charge two battery systems. Voltage sensitive relay cuts in at 13.3 volts and cuts out at 12.8 volts to ensure your primary battery is always charged and ready to start your vehicle. It's like having two separate power sources for each battery while only having one alternator! Fits a wide variety of vehicles -like having two separate power sources, the dual battery isolator kit enables your accessories to run from a separate battery while the engine is not running on your vehicle while keeping your main battery charged and your vehicle always ready to go and start when you want it. Suitable for 12v 4wd, marine, truck, caravan & camping applications Specification: Size: 69 X 69 X 57.7mm/2.71 X 2.71 X 2.27inch Rated Voltage: DC12V Merging / Open Circuit Voltage: DC13.3V/12.8V Continuous Rated Current: 125A Intermittent Current Rating: 140A Power Consumption: 10ma (Standby) / 330ma (Pull In) / OMA (Storage Mode) Terminal Stud: M6 (1/4) Package Includes: 1 Piece 12V Dual Battery Smart Isolator