How to use the alcohol tester  1. Press the button for 1 second to turn on the phone, the backlight and the display will light up at the same time, the entire content will be displayed and a beep prompts to turn on.    2. The display shows "Warm up" and a 10-second countdown. After the countdown is over, there will be a beep, prompting to enter the next stage at the same time.    3. The display shows "Blow" and a 10-second countdown. Blow for 3-5 seconds. After the countdown is over, you will be prompted to enter the result display. The test result is displayed in two units: %BAC and g/l .    4. When the test result is less than 0.02% BAC, the green indicator light is always on.    5. When the test result is greater than or equal to 0.02% ABC and less than 0.05% BAC, the yellow indicator light is always on, the "Caution" icon on the display flashes, and there is a slow beep sound.    6. When the test result is greater than or equal to 0.05% BAC, the red indicator light is always on. The "Danger" icon on the display screen flashes, and there is a rapid beep sound. The test result shows that the time is 10 seconds.