What is Sidetone and how do I enable or disable it on the G435?

Sidetone lets you hear your own voice while communicating with other people, mirroring the experience of talking on a phone so you can adjust your speaking volume to a proper level. To enable Sidetone, double press the Mute button — the LED will flash twice in orange. To disable it, double press the Mute button again — the LED will flash once in orange.