Moto Watch 100 can take SpO2 (blood oxygen saturation) readings throughout the day and automatically track SpO2 levels while you sleep. To take an SpO2 reading on the watch, follow these steps:

1. Rotate your wrist or press the upper physical button to turn on the screen
2. From the watch face, swipe left or right until you find the SpO2 widget. You will be asked to check that the band is snug on your wrist and then the SpO2 icon will be shown during the measurement.
3. Remain still and calm with your arm relaxed for up to 2 minutes while the device takes the reading.
4. After a short time, the device will show the SpO2 reading.

You can view more information about SpO2 and consult the history from the Moto Watch app on your mobile device, under the Wellness tab. Additionally, you can view the SpO2 widget from the application by following the steps below:

1. Rotate your wrist or press the upper physical button to turn on the screen of your Moto Watch.
2. From the watch face, press the upper physical button again to open the application list.
3. Scroll down and tap "SpO2": If you can't see any SpO2 data, make sure you are wearing your Moto Watch and that the band is snug but comfortable.

The sensor is positioned on the back of the watch and should not be blocked or covered, thus preventing contact with the skin.

In some cases, tattoos can cause interference with the heart rate sensor. If you experience problems, try placing the watch in areas free of tattoos.