Product name: Portable alcohol tester Sensor: High-precision sensor Test range: 0.000-0.199% BAC Charging input: DC 4.5V Dimensions: length*width*height 90x47x23mm Working environment: -5-45 1. When using 1 for the first time, please prepare 3 AA dry batteries, remove the battery cover, install the battery cover before use (battery is not included in delivery) 2 Press the power button. 3. " for 1-10 seconds. Start the machine and enter the 10-second preheat countdown. Please wait for the warm-up time. 4. After preheating is completed, it will automatically enter a 6-second countdown for air blow detection. Wait for the test results to appear. 5. Set the display unit: After completing the operation 2.3.4., if the display result appears within 5 seconds, short press once to switch to measurement display unit. (e.g. % BAC - US g/l - Europe mg/L BrAC - Japan). 6. Short press the power button twice in the off state to turn on the emergency LED lighting; short press the button when the light is on to turn off the emergency LED lighting. Please note that when the alcohol tester is first taken out of the package or has not been used for a long time, a amount of gas and other impurities will adhere to the sensor. In this case, you need to press the power button several times to preheat and clean the alcohol tester. Colour:black+white Material:abs Package Contents: 1 x alcohol tester (delivered without 3 AAA batteries) Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.