Yamaha TW-E3C True Wireless Earbuds (Red) - Manual (Page 18)

Remaining Battery Power
After this product is turned on, the audio message in the earbuds tells you how much battery power is left.
(
Audio messages:
(
Battery High: plenty of charge remaining
(
Battery Medium: moderate charge remaining
(
Battery Low: small amount of charge remaining
NOTE
You can check the remaining battery power of the charging case in the following situations.
( While charging the charging case
( Right after placing the earbuds into the charging case (except when the charging case itself is charging)
Related links
“Charging the charging case” (p.14)
18
Charging and Powering > Remaining Battery Power