I can finally use a heart rate monitor with my iPhone 4. The receiver allows you to connect your smartphone to a heart rate monitor if it is not compatible Bluetooth Smart. Impeccable with my iPhone 4. cons difficult to connect it with a lot of different cover or shell, because they prevent effective push the plug all the way. From my side I use it so unprotected, pity ... Product unfortunately incompatible with the BlackBerry Z10. Indeed although the phone is Bluetooth enabled BlackBerry Runtastic the application does not provide the connection with a cardiofréqencemètre. I was fine to install the Android app on my BlackBerry (that offers this type of connection) but the application does not recognize unfortunately Runtastic receiver.