[High Accuracy and Fast Sensor] The alcohol tester is equipped with professional airway design and high precision semiconductor sensor. Quick and accurate display of blood alcohol content. Then you can decide whether to drink and drive. 【Easy to use】 Simply insert three 1.5V AAA batteries, connect the suction nozzle, press the start button to start the countdown , preheat for 10 seconds, puff into the inhaler 5 times within 10 seconds, the blue backlight LCD screen displays the test and directly calculates the results and displays the results After that, you can press the power key to switch d 'unit. [Auto alarm function and power saving mode] There are 3 units of measurement: % BAC, ‰ BAC and mg/L selectable During a test, if the measurement result exceeds 0.5 BAC, the breathalyzer issues an audible alarm warning. When no operation is performed, the breathalyzer will automatically shut off to save power. [Compact and portable design] Mini alcohol analyzer, small enough to fit in your car, handbag , backpack or briefcase. It is convenient to have a carrying case that perfectly holds the breathalyzer and the mouthpiece anywhere. The product does not come with batteries. Note: the data is all measured manually, please allow 1-3cm error, due to the difference in light and display, there will be a certain color difference, the actual object received shall prevail.