1. How to turn on the power: Press and hold the power button, and the first test takes about 35 seconds to stabilize. Then the test results will be displayed on the screen.2. How to turn off the power: You can turn off the power by pressing and holding the power button.3. How to adjust the screen brightness: Press the M button to switch between the three gears of screen brightness.4. How to switch between Celsius and Fahrenheit: Press the power button to switch between Celsius and Fahrenheit.5. How to alarm, press the alarm button.Specifications:Item Name: CO DetectorScreen Type: Ultra High Definition TFT Color ScreenBrightness: AdjustableDisplay Mode: 1.9 inch ultra-high-definition color screen.0~50ppm(green/safe),51~100ppm (yellow/needs attention),101~200ppm (orange/warning),201~1000ppm (red/dangerous).CO :50-100,the alarm sounds 3 per 3 minutes;CO :101-200,the alarm sounds 5 per 3 minutes;CO 200,the alarm sounds 10 per 1 minute;If the detector breaks down,the alarm sounds 10 per ,the screen displays 9999.Resolution: IPS 240*280Preparation time: About 35 secondsData update frequency: 2 seconds3 in 1: CO concentration/Humidity/Temperature detectionCO detection range: 0 to 1000PPM (10PPM or 5%)Temperature range: -10 to 50(1C)/ -14F to 122 F(2F)Celsius and Fahrenheit: ConvertibleHumidity detection range: 0-95%RH (2%RH)Battery capacity: 1000mAH, with power indicatorBattery model: 803040Charging interface: USB Type-CWorking voltage: 5VUsage time: About 14 hours (depending on screen setting)Material: ABS+PCcolor: blue+whitePackage Contents:1 x carbon dioxide detector 1 x USB data cableOnly 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 +/- 1-3 cm.