1. How to turn on the power: Hold down the power button and the first test will take about 35 seconds to stabilize. After that,the results of the test will be displayed on the display.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 KEY to switch the third gear screen brightness.4. How to switch between Celsius and Fahrenheit Press the power button to switch between Celsius and Fahrenheit.5. How to the warning, Press the to alert the key.Specifications:Item name: CO DetectorScreen type: Ultra High Definition TFT color screenBrightness: AdjustableDisplay mode: 1.9in 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 warning sounds 3 per 3 minutes;CO :101-200,the warning sounds 5 per 3 minutes;CO 200,the warning sounds 10 per 1 minutes;If the detector brokess,the warning sounds 10 per ,screen shows 9999.Resolution: IPS 240*280Preparation time: About 35 secondsData refresh 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: SwitchableHumidity detection range: 0-95%RH (2%RH)Battery capacity: 1000mAH, with power indicatorBattery model: 803040Charging interface: USB Type-CWorking voltage: 5VUse time: About 14 hours (depends on screen adjustment)Material: ABS+PCcolour: blue+whitePackage Contents:1 x Carbon Dioxide Detector 1 x USB datacableOnly 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.