High Accuracy & Fast Sensor The alcohol tester comes with a professional airway design and a high-precision solid-state sensor. Accurately display the blood alcohol level quickly. You can then decide to drive after drinking. Easy to Use Simply insert the three 1.5V AAA batteries, then connect a mouthpiece, press the start button for the initialization countdown, warm up for 10 seconds, blow into the inhaler for 5-10 seconds, the blue backlit LCD display directly displays the test result. Automatic Alarm Function & Power Saving ModeThere are 3 measurement units to choose, %BAC, BAC, mg/L, when the test is performed, if the measurement result exceeds 0.5BAC, the breathalyzer will warn with an auditory alarm. The breathalyzer automatically shuts off to save money.