Yamaha TW-E3C True Wireless Earbuds (Red) - Manual (Page 14)

Charging the charging case
To charge the charging case, connect the included USB power adaptor.
CAUTION
( The charging case is not waterproof. Do not expose this product to liquids such as sweat, rainwater or seawater.
( Be sure to use the USB power cable that was included with this product.
( When using a USB power adaptor, be sure that the commercially-available adaptor is compatible with 5 V DC (at least 0.5 A)
power output.
( When charging this product inside of China, be sure to use a USB power adaptor that is approved by CCC.
( Recommended charging temperatures: 5ºC–40ºC
Type A
Type C
USB power adaptor
(commercially available)
Front
Charging indicators
1
Plug the USB power cable (type C side) into the charging case.
2
Plug the USB power cable (type A side) into the USB power adaptor.
3
Plug the USB power adaptor into the power outlet.
Charging will begin. Charging takes about 2 hours.
While the case is charging, the indicators light up as shown below.
Remaining battery power Indicator
100%
75–100%
50–75%
25–50%
0–25%
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Charging and Powering > Charging the charging case