Our app should support all Smart sensors (only chest straps).
Compatible Hear Rate Monitors (Bluetooth smart) we can guarantee to work with our app are: 

If you are using some other Heart Rate Monitor using Bluetooth Smart you need to test if it is compatible. 

If you have any problems connecting your Smart device, please check:
- that your phone has  Bluetooth Smart Support
- that the monitor is not connecting to any other app
- remove the monitor from your phone's Bluetooth settings and  connect it directly from the app settings 
- while pairing on some devices you may need to turn on location service and turn Wifi off