AUSounds AU-Stream ANC Manuel D'utilisation page 6

BLUETOOTH FEATURES
Automatic connection
The AU-Stream ANC stores your last connected device in memory. If
your earbuds are disconnected due to being out of range, they will
automatically reconnect once in range. If it is disconnected for more
than 30 minutes, select the Bluetooth name in your device to
connect again. If it is disconnected for more than 2 hours, it will
automatically shut down.
Automatically switch between left and right ear
Removing either the left or right earbud from the charging case will
switch the mode to single ear state and only play audio through the
remaining active earbud.
Reset
Place the earbuds in the charging case, press and hold the base
button for 10 seconds. Once the LED indicator flashes 3 times, the
pairing record is cleared. (Andriod devices vary by system)