The breathalyzer must use Smartphone with Android 4.30 or later version, and equipped with Bluetooth 4.0. This breathalyzer is accuracy with fuel cell sensor, and you can connect to your Smartphone by Bluetooth with auto-pairing. It is so easy to use.You may share test result with your family or friends by message, Facebook or Twitter. The power supply is 1 piece AAA alkaline battery, which you may purchase and replace easily. The battery may use about 300 tests or 12 months.There is a function of sober estimation on APP, which calculate the rough time for sober and safety alcohol level. It reminds you the time for next test.