Yamaha TW-E3C True Wireless Earbuds (Red) - Manual (Page 17)

Turning off the power
When you put the earbuds back into the charging case, the earbuds turn off.
1
Place the earbuds in the charging case.
The earbuds will turn off and enter charging mode.
NOTE
If you want to turn off the earbuds without putting them back into the charging case, long-tap the Touch Control on
earbuds (L) and (R) for around seven seconds. The “Power Off” audio message plays in the earbuds, and the indicators will
display as shown below.
Lights up for 1 sec
7 sec
17
Charging and Powering > Turning off the power