Maxcom FW51 Crystal User Manual page 5

BLOOD OXYGEN
It'll take around 30~60s to finish detecting blood
oxygen while the sensor will flashing green light, and
the watch will vibrate to remind when it's done. Please
wear the watch the right way if the watch display the
remind instead of value. (this is based on PPG for refre.)
MINDFULNESS
You can select 1min or 2mins to start the mindfulness
training, inhale while the icon increase and exhale while
the icon decrease.
WOMEN HEALTH
The female user can track health in the App after
connected.
MUSIC
You can control phone music play/pause, also adjust
volume and change music after connected with App.