Coupled easily with S-health on a Galaxy S4 (a ride in the app settings) gives the live Heart Rate. I could not make it work with other apps (runastic, polar beat, Endomondo ...) Good material. To operate a cardio belt (today) on Android, you need a compatible smartphone smart bluetooth (bluetooth 4) run on Android 4.3 minimum and that the app recognizes the belt in its settings. It must surely also be flanging "owner" for I have a Galaxy Note 3 with Géonaute decathlon-belt bluetooth smart (half the price) which rotates with Runtastic and Polar Beat but not with S-health. In short, make inquiries before ...