but I could not prove it. This morning I took it back to the store because it did not seem to be compatible with the iPhone 5. The sales associate was very helpful and showed me how tho it never worked in the store, we decided that it was because the unit was not fully charged and neither was my phone. So I returned home with it charged it fully and attempted to get it to work. I read and re-read the manual and the trouble shooting section. Bluetooth worked, it seemed. The App seemed to work. Over and over, possibly 30 or more times I started the unit and waited through the testing time. Each time the process failed due to a 'communication error". I tightened the wrist piece, loosened the wrist piece, the repositioned my arm multiple times. I did everything I could think of. I decided that I had had enough and returned again. I got my money back this time. This may work actually but it is too complicated for me.