You can check the battery level in two different ways when the headset is powering on.
When the headset is powering on, the red LED flashes rapidly indicating the batter y level.
4 flashes = High, 70~100%
3 flashes = Medium, 30~70%
2 flashes = Low, 0~30%
Voice Prompt Indicator:
When you power on the headset, keep pressing the Jog Dial and Phone Button simultaneously for about 3 seconds until you hear three high tone beeps. Then you will hear a voice prompt indicating the battery level. However, if you release the buttons as soon as the headset turns on, you will not hear the voice prompt for the battery level.