"Sentinel Three" is the original clockface for monitoring the blood-glucose levels of 3 people who have Nightscout accounts/websites. This clockface is considered legacy and is no longer updated. However, clockface "Sentinel" supports the monitoring of 1-3 people and it is recommended that those interested use Sentinel instead. There is also a Facebook group called Sentinel where members can help test the latest experimental versions and give feedback before they show up on the public Fitbit Gallery.