M100: How to Check the Battery Level
How do I check the battery level on my M100 headset?
You will hear the available talk time when you turn on the headset, as well as at the end of each call. To check the battery level in between calls, simply turn the headset off and back on again. iPhone users are able to check the battery level right on their phones. The headset battery meter appears in the upper right corner of the screen, to the left of the iPhone battery meter (see below).