Quickly estimate your blood alcohol concentration with this small and non-contact breathalyzer. No need to worry about forget to install the mouthpiece or hygiene problem, you can directly blow into the tester without mouthpiece, more convenient and safe. Portable to carry it with you, testing your blood alcohol concentration anytime, anywhere. How to use: 1. Press and hold the power button for 1 second, the alcohol tester's LCD screen turns on with one beep. 2. Warm-up mode countdown for 10 seconds. 3. Countdown test mode from 10.00 to 00.00 after warm-up mode to blow during this period. 4. Blow into the inhaler for 3-5 seconds at normal power after taking a deep breath. 5. Read the test result on the LCD of the alcohol tester. 6. Test range: 0.00% -0.19% BAC and 0.0-1.9 g / L 1. When using the tester for the first time, or after a long period of non-use, press the power button and try several times if possible. 2. Repeat 2 or 3 times for more accurate results. 3. Do not smoke or eat for 20 minutes before the test. 4. The test result is for reference only. 5. Rechargeable battery via USB cable