Clipper Battery Monitor Bluetooth. The BM-1(BT) will monitor yourboat or caravan's lead-acid batteries and transmit the data directly to your mobile phoneor tablet wirelessly by bluetooth. A simple Android app freely available from the nasamarine.com website or Google PlayStore (requires Android V4.3 or later) shows your service battery voltage current flowingin or out state of charge and time to charge or discharge the battery. An audible alarmwarns if the battery level gets dangerously low. It will also show the starter batteryvoltage. For apple users a more sophisticated app with additional Specifications for Clipper Bluetooth Battery Monitor: Manufacturer: Clipper Color: Black Package Contents: Clipper Bluetooth Battery Monitor Clipper BM-BT: Battery Monitor Bluetooth