Six measurement units: There are six common measurement units for you to choose (%BAC, BAC, mg/L, g/L, mg/100ml, ppm). The measurement range of each unit is 0~0.2% BAC, 0~2BAC, 0~2g/L, 0~1mg/L, 10~200mg/100ml, 25~500ppm. High precision: high-sensitivity semiconductor sensors are used, with fast detection speed and accurate results. Can give a quick result to see if you can drive. Portable Design: The alcohol breathalyzer is only 4.4 inches * 2.4 inches * 1.1 inches, saving space and light weight. It is easy to hold and carry. So it can easily fit in a purse or pocket. Auto Power Off: Powered by 3 AAA batteries (Note: Batteries are not included), you can test them more than 200 times each time you install a battery. Automatically shuts off 3 seconds after completing the test to save power. Easy to use: Press and hold the power button for 2 seconds to turn on, enter the "preheat" mode, wait for 15 seconds to warm up, enter the "blow" mode, and then continue to blow for 3-5 seconds to get the result. The result will be displayed on the LCD for 15 seconds, in the result display mode, press the "Power" key to switch the test unit (%BAC/BAC/mg/L)