Frequently Asked Questions

What is O2 Score?

O2 Score is a measure of oxygen shortage during whole sleep. It combines frequency, duration, and depth of oxygen drops. A higher score means oxygen is richer. If it's yellow or red, please ask your doctor for advice.

Where can I find more guidance about the report? 

Click the question mark in the upper right corner of the APP report page.

Do I need to pair Bluetooth?

DO NOT PAIR in the system settings of your phone. Make sure the Bluetooth is enabled on your phone and device’s battery is not out.

Why do I need to allow Location access for Android?

With android phone, you need to allow Location access to make Bluetooth work. We DO NOT collect your location data.If you have refused the permission, you can try following steps to allow the access: 

1)Reboot your phone; 

2)Turn on “location”on your phone; 

3)System settings -> Apps-> ViHealth, allow location access.

Why I can’t connect device with App after updating iOS system software?

If you can’t connect your device after updating iOS, please try the following steps: 

1)In the system settings, turn off and turn on Bluetooth; 

2)In the Control Center, tap the Bluetooth icon repeatedly to re-enable Bluetooth. 

Turn on device, run App to connect it.

How to sync data?

Take off the device. After the countdown, the data will be ready for sync. 

1)After the countdown, open App to sync data. 

2)Or next time after you turn on your device, open App to sync. 

If measurement time is less than 2 minute, there will be no data.

When recording, do I need to open App?

The device has built-in storage, it is not necessary to open App.You can open app to change some settings of device.

How many sessions of data can be stored?

The device can store last 4 sessions, up to 10 hours for each.

Which finger is recommended ?

The ring is elastic, inside circumference range is about 2.0~3.2 inch. 

Thumb and index finger are preferred.

General rules: 

1)Do not use middle finger. 

2)Avoid loose wearing

Can it be used during fitness?

Generally speaking, yes. However, frequently movement may make the readings unavailable.Usually, the readings will recover in a few seconds after stop moving.

How to power on?

Wear the device on your finger, it will power on automatically. If can’t power on, charge you device first.

How to power off the device ?

Take the device off your finger, it will power off automatically in a while if not connected to App.

If the battery runs out during use, will the data be saved?


Can I change the settings of vibration?

Yes. When you connect the monitor to your phone, you can turn on/off the vibration, change intensity or threshold.

How to correct device time?

Connect to your phone, device clock will follow your phone time automatically.

Can the screen be always on?

Yes, you can set the screen mode in App. Battery will runs out a bit faster in the Always On Mode.

How to wake up the screen when it goes off?

Touch the key on the top of device, you can wake up the screen. You can also check time and battery with the touch key.

Why I get different readings by Oxygen Monitors of Wellue and other manufacturers?

Please be assured that all Wellue products provide medically accurately measurement.

Different manufacturers utilize algorithms with different average SpO2 times, which is a significant element when calculating the reading. The shorter the collecting duration, the more sensitive the result, the fast the response. Oxygen monitor with too long assessment time is not the best choice for oxygen saturation detection, especially during sleep. Wellue’s intelligent averaging algorithm collects data quickly and identifies the precise SpO2 value. 

Therefore, it is not rigorous to compare oxygen monitors that utilize different averaging algorithms.The comparing result will be much more accurate if obtained by an arterial blood gas.

Could I log my data in the Apple Health?


I use OSCAR to analysis my CPAP treatment, how to import my data in OSCAR?

OSCAR 1.1.0 supports the Wellue pulse oximeters listed below. 

Wellue SleepU

Wellue O2Ring

Wellue Check Me O2

Windows PC

Download and install Viatom's free O2 Insight Pro software. [link]

Connect your O2ring to your PC with the USB cable that came with your oximeter. The O2 Insight Pro window should say "Device connected" in the bottom right corner. Viatom's software cannot connect via Bluetooth. You must use the proprietary USB cable that came with your oximeter.

Click Download.

The downloaded session files will be stored in C:\Users\YourUserNameHere\AppData\Local\O2 Insight Pro\DATA\SerialNumber.


Download and install Viatom's free O2 Insight Pro software. [link]

Open the O2 Insight

Turn your oximeter on by inserting your finger into the probe momentarily until the time shows on the display.

From the O2 Insight Pro software click the "Connect" button in the top left of the app window.

Another small window will open which should show your oximeter. Click the "Connect" button next to your oximeter. The O2 Insight Pro window should say "Device connected" in the bottom right corner.

Once your oximeter is connected to the app, click "Download". Once the download is complete the file needed to import the oximetry data into will be available.

When finished, click the "Disconnect" button at the top left of the O2 Insight Pro window.

The downloaded session files will be stored in: /Users/YourUserNameHere/Library/Containers/com.viatom.O2PCViewer-BLE/Data/Library/Application Support/O2_Insight_Pro/DATA/SerialNumber/.

The "Library" folder is hidden by default, but you can still reach it in Finder by pressing cmd-shift-G and entering ~/Library in the file selection dialog.

Syncing your Oximeter times with OSCAR

To synchronize your Oximeter start time with your CPAP data:

Import your CPAP data into OSCAR. In the left panel on the Daily screen, under your AHI, you will see the start time for your CPAP session. Make a note of this time.

If you are using the O2 Insight Pro software make a copy of the Oximeter binary file and store it in a different folder.

If you are importing the Oximeter binary file from your phone to your computer then select the file from the folder you stored it in.

The name of the file is in the format YYYYMMDDhhmmss (YearMonthDayHoursMinutesSeconds) with no extension. The time in the filename is 24 hour time (221500 = 10:15:00 PM)

Using your file manager (Finder for Mac, File Explorer for Windows) right click on the Oximeter binary file and select "Rename" then change the last 6 digits of the filename to match the start time of your CPAP session that you made note of earlier. Then hit the Enter key to save your change.

The Oximeter binary file can now be imported into OSCAR and will have the same start time as your CPAP data.

Import the Downloaded Sessions into OSCAR

Select Data > Import Wellue Data in OSCAR's menu bar.

Navigate to the folder where your downloaded session files are stored. See above for the location, depending on how you downloaded the data from the device. The session files are named after the time at which each night's recording started, e.g. 20220408214533 for April 8, 2022 at 9:45:33 pm.

Select the folder containing the session files and click Open. All sessions in that folder will be imported, and previously imported sessions will be skipped.

Alternatively, if you want to import only a single session, you can select just that session file.

Note: On Windows, you cannot directly open a folder. Shift-click to select more than one session file in the folder, and all files in that folder will be imported.

How can I make the band smaller to fit my skinny fingers? Stuffing tissue in it does not work and no tape will stick to it.

O2Ring could fit most size of adults' finger,  if thumb is too skinny, MiniRing  maybe a better choice.