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 battery 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 the Phone Button simultaneously for about 3 seconds until you hear high tone triple beeps. Then you will hear a voice prompt indicating the battery level is high, medium, or low.
If you pair the headset with an iPhone, you can check the headset’s battery next to the Bluetooth icon on the phone’s screen.