1 - High Accuracy Test - The breathalyser has a high-precision semiconductor alcohol sensor. It delivers fast and accurate results to determine if you are ready to drive. The alcohol measurement range is between 0.000 and 0.199% BAC. (It is recommended to use the alcohol tester 20 minutes after drinking alcohol to ensure the accuracy of the test.) 2 - USB charging - alcohol tester police accurate is equipped with a USB charging cable, which can be used on a single charge for about 500 tests, can be reused many times, environmentally friendly and durable. The updated version of the professional alcohol tester can display the latest 50 test datasets. 3 - Alarm Function - Test result 0.15-0.24mg/L: Buzzer BB...BB...Short alarm. The test result exceeds 0.25 mg/L: Summer BBB... emergency sound alarm, promille meter protects your safety. 4 - Easy to use - our alcohol tester police accurate is cleaner and more hygienic than the conventional alcohol meter. No need to blow into your mouth. Turn on the professional alcohol tester, wait 10 seconds to warm up and then blow for 3-6 seconds, the result will be displayed on the LED screen. The results are displayed for 10 seconds and then automatically switched off. 5 - Lightweight and portable - this mini alcohol tester police-accurate takes up little space and features a key ring design. You can attach it directly to the keychain of the car at any time for easy testing. Suitable for personal use, home, social events and certain industries where alcohol testing is required.