This type of kit is suitable for caravans, Motor homes, 4x4s, Day caravans, Mobile workshops, Cars or Boats. Voltage sense systems are especially suited for modern vehicles with canbus controlled wiring as this type of kit does not need an ignition feed or any additional wiring and are very simple kit to install, all you need to do is to connect your battery to your leisure battery(s) by using the kit supplied, with very easy to understand fitting instructions and a wiring diagram. The voltage sense relay simply detects the rise in voltage from you vehicles charging system to allow you to charge your leisure battery(s) while your engine is running. When your engine is switched off, the relay isolate your leisure battery(s) from your main battery. So it does not drain your main battery and you always be to start your vehicle. You be supplied with everything you need to fit this kit Dual Battery Isolator Kit Different batches The screws and terminals may be inside the back cover of the