Used to start recording audio from the built in microphone.
Press a second time to stop recording.
There are three controls.
The play button
Click it to begin playing your audio from wherever the cursor is, click again to pause playback.
The double arrows alongside allow you to skip through your audio.
The back arrows move the playback position to the beginning of the current chunk or the beginning of the preceding chunk.
The forward arrows move playback to the next chunk