1---Sensitivity & High Precision: With its high-precision semiconductor alcohol sensor, the alcohol tester breathalyzer will give you accurate results and beat alarm when too much alcohol is detected. 2---Automatic Alarm Function: The Caution symbol is displayed if the alcohol concentration is between 0.02% BAC(or 0.2g/l) and 0.05% BAC(or 0.5g/l). The Danger symbol is displayed with beep audible alert if the alcohol concentration is greater than or equal to 0.05% BAC(or 0.5g/l). 3---Easy To Read LCD Display: With the LCD display, it is easy to read even in less than optimal light conditions and show how drunk you are. 4---12 Easy to Wear Mouthpieces Included: The portable breathalyzer alcohol tester comes with 12 individual mouthpieces. The mouthpieces can be cleaned and reused. Ideal for your family or friends to test. Test yourself, your friends and family with the different mouthpieces. Drive safely and protect your family. 5---Easy to Use: Just keep pressing the power button for 3 seconds to start the breath alcohol tester. Wait for 10 seconds for preheating and then keep blowing for 3-5 seconds to get the result. The result will be displayed on the LCD screen for 15 seconds. Then the blood alcohol level tester will automatically power off. NOTE: To obtain more accurate result, please use it after stopping drinking alcohol for 20 minutes and test repeately 2 to 5 times.