One button operation The breathalyzer is extremely easy to use. Simply insert the three 1.5V AAA batteries, press the power button for 1 second to turn on the alcohol tester, perform a 10-second warm-up, blow into the breath inhaler for 5-10 seconds, the backlit LCD display blue directly shows the test result .The third measurement is the most accurate.Compact and Portable Design The alcohol analyzer With mini size, small enough to put in your car, bag, backpack or briefcase, making it easy to take it anywhere. wherever you go. High-precision and fast sensor Alcohol tester with advanced semiconductor sensor technology, you can get the accurate blood alcohol concentration, and then judge whether you can drive or not. 3 Unit of measure There are 3 units of measure to choose from, % BAC, BAC, mg/l. When after drinking, it is recommended to wait 20 minutes before taking a test, it is because 20 minutes is approximately for the alcohol to enter. blood from the digestive organs. Wait at least 3 minutes to start the next test after the last test.