After I had first a significantly cheaper chest strap (see my other reviews) ordered, but did not work, I finally ordered this chest of Polar. On my LG G2 (Android 4.4.2), the coupling was completed within a very short time, although the LG G2 is not listed on the website at the Polar compatible devices. Use the belt now with Endomondo so that it works perfectly. Runtastic I briefly tested, and therefore has the belt works.