VB Power Simple Voltage Display 1-6S Lipo Voltage Meter.
Lipo battery low voltage buzzer alarm. This micro device can measure lipo from 7.4v to 14.8v (2s to 4s), it will sound up to 95dB if your lipo cell voltage drop to 3.3v. It is also a good device for a quick test before getting into a fight, and you can use it as an infight alarm if you're not sure about the maximum fight time. MUST HAVE ITEM TO SAVE YOUR LIPO!