For TRE, Vasa Blå and TIO:
Press the middle and upper buttons (VOLUME +) simultaneously.
To deactivate voice assistant, press the two buttons simultaneously again.
Siri needs to be activated on your device first. You can give the command "HEY SIRI" through the earphone's microphone once Siri is activated.
To activate voice assistant, press and hold the button until you hear the first beep. Note that keep holding after the first beep, NIVÅ will be turned off.