Pryme Synergy wired, amplified remote speaker microphone for use with Motorola SL7550, SL300 and TLK100 WAVE Two Way Radios. These radios do not have the power from the board to properly boost audio to the microphone. The SPM-600-M8AMP has a built in battery and requires charging. An AC wall charger is included in the package. Status LED on the back of the microphone (red or green) lets the user know the charge status.