Polar WearLink+ Transmitter with Bluetooth heart rate sensor is a transmitter designed to sync up with certain apps on your smart device.How do I measure heart rate with Polar WearLink+ Transmitter with Bluetooth heart rate sensor?The sensor works together with these mobile applications:- Endomondo (www.endomondo.com)- SportyPal (http://www.sportypal.com/)- RunKeeper (http://runkeeper.com/)- Cardio Trainer (http://www.worksmartlabs.com/cardiotrainer/)- Runtastic (http://runtastic.com/)- Run.GPS (http://www.rungps.net/)The applications might work on different mobile operating systems (e.g. Android, Symbian). If your mobile phone is not supported for one application, have a look if you could find it supported for another.Polar WearLink+ Transmitter with Bluetooth heart rate sensor is not compatible with Polar training computers, only mobile applications.What Bluetooth 2.0 supported mobile phone should I use?Polar recommends following phones to be used with WearLink+ Transmitter with Bluetooth heart rate sensor:Android phones:- HTC Wildfire S, Desire S, Sensation XE, One SV (LTE)- Samsung Galaxy Ace S5830i, Galaxy Gio GT-S5660, Galaxy S i9000, Galaxy Y GT-S5360, Galaxy Xcover GT-S5690 , Galaxy Mini GT-S5570, Galaxy S4 GT-I9505- LG Optimus 3DSymbian phones:- Nokia 5230- Nokia 5530 OMU, 5530 Xpress Music- Nokia 5630, 5630 OMU- Nokia 5700 XpressMusic- Nokia 6110 Navigator- Nokia 6290- Nokia 6700 slide, 6710 Navigator, 6760 slide- Nokia C5-00, C5-03, C6-00, C6-01, C7-00- Nokia E5, E52, E63, E66, E7-00, E71, E72- Nokia N76, N8-00, N97 mini, N97 mini OMU- Nokia X6 OMUPolar heart rate sensor is not compatible with Apple iPhone and Windows Phone even if you can run an above application on it.