How to Use: 1. Press the button for 1 second to turn on, the backlit and the display screen will light up at the same time, display all the content and there will be a "beep" sound to prompt. 2. The display screen shows "Warm up" and 10 seconds countdown, after the countdown is over, a "beep" will sound, and will enter the next stage. 3. The display screen shows "Blow" and 10 seconds countdown, blow to the blowing place for 3‑5 seconds, after the countdown is over, a "beep" sound will prompt, the test result will be displayed in two units of %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% BAC and less than 0.05% BAC, the yellow indicator light is always on, the "Caution" icon on the display screen 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 flash, and there is a rapid beep sound. The test results show a time of 10 seconds. Specification: Item Type: Alcohol Detector Material: ABS Model: G1 Battery: 602030 lithium battery 3.7V 300mAh (built in) Application: Alcohol detection Basic Parameter: Test Range: 0.000-0.199%BAC Package List: 1 x Alcohol Detector 1 x USB Cable 1 x Manual