High Accuracy Electronic BreathalyzerThis breathalyzer uses high precision semiconductor alcohol sensor, it will tell you exactly whether you can drive the car at the moment. Unique designNon-contact use, no need for a mask, more convenient to use. An instrument that analyzes blood alcohol concentration anytime and anywhere. Our professional breath alcohol tester is small and easyto put in a purse or pocket. Auto Alarm3 colors to remind wine test results. Green is for safety, yellow for warning and red for danger. If the test result greatly exceeds the limit, the red light of the breath testernumber flashes. Powered by USBBreak the traditional battery charging, turn on the power and have a longer service life. The alcohol tester can easily be charged via USB cable. Professional Breathalyzer: Press and slide down to display WAPM UP sign for 10 seconds, then blow, then display BLOW to blow, and RESULY means to read the value. After the OFF sign beeps twice, it will turn offautomatically.