Fast and Accurate Results The portable breath analyzer is designed with a sensitive sensor system to provide you with highly accurate results in seconds. With the help of indicator lights, you can tell at a glance whether you are ready to drive. Easy to use Just insert two AA batteries (batteries not included), then just connect the mouthpiece, turn on the breath alcohol tester, wait for 15 seconds to warm up, then blow evenly for 3-5 seconds, the results will be displayed on the LCD Within 5 seconds. Note: For more accurate test results, please wait 20 minutes after drinking alcohol before using the breathalyzer. Colorful Lights and Audible Alarms When the measurement exceeds 0.5 BAC, the breathalyzer emits an audible alarm to remind the user that you are drunk. If it is greater than 0.05%, the red light will be on, otherwise, the green light will be on. When the battery is low, the yellow LED will light up. After the test results are released, it will automatically shut down for 15 seconds to save battery consumption. Portable and Compact This lightweight breathalyzer easily fits into your car, handbag, backpack or briefcase, saving you space and perfect for weddings, parties, banquets or other social events to ensure you drink Safe Driving.