This high-precision semiconductor alcohol tester is very easy to use, just press a button to operate, and secondly it has a built-in rechargeable lithium battery (3.7V,1000mAh), and with a micro USB charging cable. Allows you to perform 500-800 alcohol tests. Just blow it into Mouthpieces to get an accurate BAC reading in a few seconds. You can take it anywhere. This is very suitable for weddings, parties, banquets or other social events. Product dimensions (L * W * H): about 126 x 51 x 23 mm Weight: 3.17 oz (90g) Detection range: 0.000% -0.199% BAC; 0.000-0.995mg / l Alert Level: (Optional) 0.050% BAC; 0.500 ‰ BAC; 0.250 mg / l; 50mg / 101ml Warm-up time: <15s Response time: <5s 1, Mouthpiece, Before blowing, Please check whether the mouthpiece is properly inserted (with 10 Mouthpieces). 2, The LCD Display, You need to wait 15 seconds after blowing, The test result will be displayed on the screen. 3, Power Button, You need to long press the Power Button, and wait a few seconds before the display. 4, Mode Button, This alcohol tester has six testing standards, Respectively, The United States, Russia, China, Europe, Poland, Japan. If you need to switch modes, you need to press the "Mode Button" before the countdown of 11 seconds after power on. 5+6, Buzzer&Breath Out, You blow into the gas will be dissipated from here, which means that you need to wait for the gas to dissipate before the second test. 7, Charging Port, This alcohol breathalyzer is with a USB charging cable, you can charge at any time and anywhere. 8, Charging Indicator, When the breathalyzer is not charged, this charging indicator will show red, after a full charge shows green. Note: 1. In order to get more accurate results, please test 3 times every 8-10 minutes to get the average value. 2. After showing the test result for 15 seconds without operation, it will automatically turn off. 3.Breathalyzer need to be tested after 20 minutes of drinking, otherwise the results will be high. 4.After powering on, if the battery level in the upper right corner of the display shows low or the display shows “Lo” and flashes, it means the battery level is low and needs to be charged. 5.The product measurement range is 0~0.199%BAC. If the alcohol content in the body reaches the maximum value of 0.199%BAC, even if you drink more, the measurement result will not increase because it has already reached the maximum value of 0.199%BAC. 6.In WAIT preheating mode, click twice in a row (M button) to enter the alarm point setting mode, press and hold for 1 second (power button) to switch between early warning point and alarm point settings, click (power button) to increase the alarm point, and click (M button) to decrease the alarm point. Result: Result A: BAC value is lower than the Warning Value, the screen shows green and the alarm sounds "Beep"; Result B: BAC value is between the Warning Value and the Danger Value, the screen shows yellow and the alarm sounds "Beep Beep, Beep Beep, Beep Beep"; Result C: BAC value is higher than the Danger Value, the screen shows red and the alarm sounds "Beep Beep Beep" for 10 seconds.