Great device !!!
I got this for my wife who was in the process to quit smoking.  She said the setup for this device was straight forward and the app is easy to use. The device is accurate, if she had a cigarette, the CO 2 numbers would be higher. For her, the CO2 number was a clear reminder of the progress that she was making. Overall she recommends this as it helped her quit smoking.
Rating: 5 stars