High AccuracyThe alcohol tester comes with professional airway design and high precision semiconductor sensor. It can test your blood alcohol level (BAC) more accurately and faster Automatic AlarmWhen the test result exceeds the alarm value set by the alcohol tester (0.05 percent BAC), the screen backlight turns red and flashes ten times and is accompanied by l buzzer sound prompt. Easy to use The Breathalyzer is easy to use. Just insert the 3 AAA batteries and press the power button to start the test. (battery NOT INCLUDED) Portable SizeSize: 14.5 x 11 x 4.5cm, weight: 200g. The alcohol test is small and light that you can test your alcohol content anytime and anywhere Warm TipsThe preheating time of this Alcohol Tester is 15 seconds and the blowing time is at least 5 seconds. To get the most accurate test results, it is recommended to test it three times (clean your mouthbefore the test)