Digital CO2 Sensor PPM Meters Mini Carbon Dioxide Detector Gas Analyzer Air Quality Monitor USB Detector TVOC HCHO PM2.5 Features : 1. HCHO (formaldehyde) detection concentration value range: 0~1.999mg/m; 2. The range of concentration values detected by TVOC: 0~9.999mg/m; 3. AQI air grade: 1~6 4. There is an over-standard alarm prompt; 5. There is low voltage shutdown; 6. Lithium battery power supply (built-in non-removable) Instructions : (1) Turn on/off: Power on: Pre and hold the power button for 1 second, and at the same time Turn on the phone after hearing a beep. Shut down: Pre and hold the power button for 5 seconds, then you hear Turn off after a beep. (2) Preheating: After power on, there will be on the LED screen every time 200 seconds automatic countdown. This is the formaldehyde sensor inspection Measure the preheating proce. (3) Calibration: After turning on, put the detector outside the window for ventilation Place for more than 10 minutes, and then quickly pre calibration Pre key 3, the instrument emits a beep (calibration succeful), The data on the LED screen will return to: 0.000 calibration carry out. (4) Detection: After the calibration is complete, place the detector Under the measurement environment, the current value is the detected value, If the standard is not exceeded, the instrument does not emit a beep. The standard values of formaldehyde and TVOC are: HCHO (formaldehyde): standard0.10mg/m TVOC: Standard0.6mg/m Specifications: Main color: White Material: ABS Screen size: 2.8in Detect error: