No, the CUE1+ is fully functional without the mobile application. 

The CUE1+ works straight out of the box. Default stimulation settings are pre-set to the parameters shown to provide benefits in our clinical trials. All our clinical trials have been conducted using the “out-of-the-box” device settings. For this reason, we strongly advise against adjusting the stimulation settings during the first 90 days of use, or without speaking with our Community Support team. 

If you do choose to connect to the CUE App, it is available to download for both Apple and Android devices:

Apple (iOS): Download on the App Store

Android: Download on Google Play