Clean rates on this screen (tap to set start and end):
Set the phone's own brightness to maximum and turn off power saving, or Chrome may drop to 60 Hz.
Only used when the phone stays in portrait. During the countdown each panel shows LEFT EYE or RIGHT EYE, so you can check in the headset; if they read sideways or swapped, flip this setting.
A soft chime marks the start and the end. Tap the screen (or the headset's button), press any key on a Bluetooth clicker, or leave the browser to stop instantly.