You must have the base unit plugged in at all times, it has an unbalanced 1/4" output straight to your amp, or a balanced XLR to a head unit or PA.The unit displays a soft LED halo light, which pulses red when your <30 mins of battery time in the receiver

The transmitter unit has a green LED light which reflects whether it is fully charged or not

It was fully charged and had the correct lights on and connection was fine

Cool indicator lights, yet could be cooler if it at least had a setting and flashed a color light show mode...to sound/passing signal or something