This handy little device gives you piece of mind, it Automatically shuts the fridge off when the battery charge drops below a set voltage, which means no more flat batteries. Also Available in a In Line model (BMIL), both have a selectable 10.5 volt or 11.5 volt cut out (plus or minus 0.1volt) (for selection please refer to vehicle manufacturers requirements for starting) and both have a LED display for easy monitoring of battery voltage. They have an automatic reconnection when the battery voltage reaches 13.2 volts (plus or minus 0.1volt), and both are rated to 15 amps. The BM12 is a hard wire version. For extra versatility the BMIL Battery Monitor In Line, this model simply screws into your Engel 12 volt lead using the 'posi-fit' connections that come standard with your Engel refrigerator, allowing your battery monitor to go where ever your Engel goes.