The LIPO alarm buzzer is an extremely useful gadget that comes in a small form factor making it easy to install in any RC vehicle (25mmx11mmx40mm). 

LIPO batteries are one of the corner stones of available technologies and are used in the RC industry because of their incredible power density and capability of unloading that power at extremely high rates.  Of course with such power comes great responsibility(Yes i know :)) and so LIPO batteries require more care and attention.  The biggest two considerations are, don't over charge or discharge the batteries. 

The LIPO buzzer assists in the latter case and can be programmed to loudly alarm when any one of the cells in the LIPO battery discharge passed a certain voltage. When you hear the buzzer, stop playing and ensure your LIPO battery have a long and happy life.