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 close the warning, Press the to alert the key. Specifications: Item name: CO Detector Screen type: Ultra High Definition TFT color screen Brightness: Adjustable Display 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 PPM:50-100,the warning sounds 3 times per 3 minutes; CO PPM:101-200,the warning sounds 5 times per 3 minutes; CO PPM 200,the warning sounds 10 times per 1 minutes; If the detector brokess,the warning sounds 10 times per ,screen shows 9999. Resolution: IPS 240*280 Preparation time: About 35 seconds Data refresh frequency: 2 seconds 3 in 1: CO concentration/Humidity/Temperature detection CO detection range: 0 to 1000PPM (10PPM or 5%) Temperature range: -10 to 50(1C)/ -14F to 122 F(2F) Celsius and Fahrenheit: Switchable Humidity detection range: 0-95%RH (2%RH) Battery capacity: 1000mAH, with power indicator Battery model: 803040 Charging interface: USB Type-C Working voltage: 5V Use time: About 14 hours (depends on screen adjustment) Material: ABS+PC colour: blue+white Package Contents: 1 x Carbon Dioxide Detector 1 x USB datacable 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.