Take Note: 1: This model does not support China version Android phone, IOS and Android (Go edition) devices 2: User needs to download the official ‘OHealth’ app from Google Play. The app is only available for smartphones with Android 9.0 and above 3: User phone should also have a GMS version of 23.45.23 and above. 4: This is Watch 3 43mm size, smaller than Watch 3