Product Function illustrate: 1.HCHO Testing Equipped with the principle of semiconductor gas sensor.Turn on for 30S to test, the range is0-9.999mg or m3, and the accuracy is 0.001mg or m3. 2.CO2 Testing Equipped with non-dispersive infrared (NDIR) principle.Turn on the device for to test,the range is 400-5000ppm,and the accuracy is 1ppm. PM2.5 Testing Equipped with Mie scattering principle can detect the dust particles in the air. Turn on the device for to test.The range is 0-1000ug or m', and the accuracy is lug or m3. TVOC Detection Equipped with the principle of semiconductor gas sensor.Turn on for 120S to test, the range is 0-9.999mg or m',and the accuracy is 0.001 mg or m'. Testing Result Illustration The results showed: super high concentration,high concentration, slightly high concentration,good and excellent. Operation Instructions 1.On or Off When the power is more than 10 percent , long press the side button to turn on or turn off. 2.Calibration Place the device in a ventilated place indoors and outdoors,click on the"About" interface, click the "Calibrate" button,and the device will beep immediately after the calibration.After 10S, the device calibration is finished. 3.Air Testing Air testing can be performed after turn on 5 minutes. 4.Touch Screen Instructions Swipe left and right to switch between different interface displays, and tap the corresponding item to enter the corresponding interface setting and switching. Color: whiteandblack material: plastic Package Contents: 1 x Air Quality Monitor 1 x Charging cable 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.