This app reconnects your watch after it has been out of Bluetooth range of the phone. The app should work at least for Fenix 3, Fenix 3 HR, Vivoactive HR, ForeRunner 235. If you have a different watch and the app doesn't work then you can try the option "Use GCM pop-ups ". But I cannot guarantee it will work since I have only tested on a Fenix 3.