Precautions for use, must read!After drinking alcohol, it is recommended to wait for 20 minutes before testing, as it takes about 20 minutes for alcohol to enter the bloodstream from the digestive system, and residual alcohol in the mouth takes time to dissipate.In order to obtain more accurate results, there should be at least a three minute interval between each test.Do not use products such as benzene, gasoline, and diluents to clean the testing instrument.Do not allow any liquid to seep into the sensor.5. Reminder: For your and others' safety, please do not drive under the influence of alcohol.For aviation safety reasons, this product is shipped without batteriesTip: To obtain more reliable records as much as possible, it is recommended to test at least 45 minutes after drinking alcohol.Our alcohol tester can accurately measure your alcohol intake, with a testing range of 0.00-0.19% BAC and 0.0-1.9g/l. After drinking alcohol, you can easily use it to test your alcohol intake and avoid drunk driving problems. It is very easy to use; You just need to blow air into it, and it will give the result after 5 seconds. This is a great little tool that can prevent you from drinking too much alcohol, and it's very small so you can carry it with you. The red LED backlight can clearly display test results even in the dark.characteristic:Brand new digital display breath alcohol testerDigital alcohol tester with sound alarmRange: 0.00-0.19% BAC and 0.0-1.9g/lQuick response and recoveryAutomatic shutdownComes with four additional mouthpiecesKeychainRed LED backlightPerfect for putting in your pocket or walletAccurateSpecifications:Color: BlackMaterial: ABSBacklight: Red LEDAccuracy: 0.01% BAC&0.1g/lPreheating time: less than 10 secondsResponse time: less than 5 secondsTest range: 0.00-0.19% BAC&0.0-1.9g/lWorking environment temperature: 10-40 degrees CelsiusWorking environment humidity: 40% -90%Power supply: 2 AAA alkaline batteries (not included)Weight: 87.0 gramsPackaging dimensions: 142.0 x 110.0 x 35.0 millimetersPackaging: Color box packagingPackaging content: 1 * backlight+20 blowing nozzles+1 * user manualAttention: The shipment does not include batteries!!!