Professional Digital Breathalyzer from amzon by ipstyle

• EASY TO TAKE ANYWHERE: Do not use the breath analyzer until it has been 20 minutes since the last drink; please wait at least 3 minutes to begin next test after last test. This alcohol tester comes with 10 mouthpieces for you to change,Dualinput for right and left handed usage
• •✔HIGHT ACCURACY - The system will automatically warm you once the test result is above 0.05%BAC or 0.50‰BAC or 0.25mg/L or 50mg/100ml. It can also be used to test breast-feed mothers to make sure they can feed their babies
• •✔SMART & FAST RESULT : High accuracy for you, The AD8800 breathalyzer is used to measure concentration of the alcohol in human body, Smart mcu control, when the test result is above 0.05%bac or 0.50‰bac or 0.25mg/l or 50mg/100ml, it will send out audio and video warning to alarm you
• •✔ENERGY-SAVING: Auto-off. Powered by 3AAA batteries( not included but commonly available), it will automatically shut off to save power after finishing the test for 5 seconds. each time you install batteries, you can test more than 200 times. Moreover, it is designed with low power indication
• •✔90 DAY MONEY-BACK GUARANTEE: We stand by all our products, but if you are unhappy with your breathalyzer, you may return it any time during the first 90 days 

Operating Instructions:

Wait 20 minutes after you drink, eat or smoke before testing.Failure to wait 20 minutes can give inaccurate BAC readings and harmthe sensor.
Step 1: Insert a mouthpiece into the mouthpiece opening.
Step 2: Press the Power/Mode Select or Button. You will hear a beep and the unit will start to count down from 15 onthe DISPLAY and say “Warm up”. This warm-up process prepares the sensor.
Step 3: When the countdown approaches 2, begin to inhale a deep breath.When the countdown reaches zero, you will hear a second beep indicating that you should blow into the mouthpiece. Blow through the mouthpiece until you hear a beep. This may happen at any point during the 10 second countdown.
Step 4: Once the sensor has analyzedthe breath sample, the estimated BAC value is displayed.
Features:•Auto-calibration & sensor fault self-checking system
• Fast response time <5 seconds
• Dual inputfor right and left handed usage
•Accuracy +/- 0.010% BAC (0.1 g/l)
•Detection range: 0.000-0.1990%  BAC (0.000‰-1.999 ‰ or 0.000-0.995 mg/l)
•Displays results in ‰BAC&%BAC&mg/L
•Operating environment 10C – 40C (50F – 104F)
• Warmup time =15 seconds  Response time = 5 – 10 seconds
•Battery life = approximately 200 tests
•Dimension: 117*61*26 mm
•Powerinput: 3*1.5 V “AAA” Battery (not included)
•Package Included:Alcohol Tester,10 pcs Mouthpieces, User Manual, Cloth bag
Troubleshooting:

If the alcohol tester provides the wrong results, than please blow into the sensor with the dry

 Source from: https://www.amazon.com/Alcohol-Breathalyzer-Digital-Portable-High-precision/dp/B075D49QG9/