SilverCrest TRUE WIRELESS BLUETOOTH STSK 2 A1 Instructions D'utilisation Et Consignes De Sécurité page 30

Checking current battery capacity status
of the charging/storage box 6 :
Briefly press the on button 9 .
The current battery capacity status is
indicated by the charging status indicator
8 on the charging/storage box:
LEDs
30 GB/IE/NI
Battery capacity status
approx . 30 %
approx . 60 %
approx . 100 %