The details of your currently installed Cartidge can be found in the Devices section in the Withings App. You will be able to see the type of Cartridge, its expiration date, and the remaining test strip measurements. When your Cartridge expires, you will also have the option to install a new one. 

To check your number of test strips remaining in your Cartridge, please follow these steps:

1. Go to the Home tab
2. Click on Devices in the top right-hand corner.
3. Find your U-Scan and tap All settings.
4. You can view Remaining measurements under 'Manage Cartridge.'