The product does not need calibration, the start can be tested, accurate detection of carbon dioxide, used in agricultural production, production warehouse, laboratory, family, etc.Large LCD display, different font colors display different air quality, green 400-799ppm, yellow 800-1199ppm, orange 1200-1599ppm, red 1600-1999ppm, 2000ppm above four colors flashing at once. /li>CO2 gas analyzer uses semiconductor TVOC sensor to calculate carbon dioxide concentration, with stable performance, low consumption and long service life.The product is compact in size and easy to carry. The vent holes on the back not only accelerate the convection between air and the machine, so as to achieve effective detection, but also provide heat dissipation effect.1200mAh large capacity battery for prolonged work, Type-C charging interface, easy charging. Product Description We we all know that air is an indispensable part of our life. Air quality affects our body and mind, but air is colorless and tasteless, we cannot measure it with our eyes. For this, we need an air tester to help you monitor the air quality. CO2 measurement range: 400-5000 ppm. Temperature measurement range : 0-50 . Humidity measurement range: 0% to 99% RH. Battery: 3.7 V, 1200 mAh. Sensor: Semiconductor TVOC sensor. Dimensions: 90 x 70 x 35 mm. Material: ABS. < b>Contents: 1 air quality analyzer. 1 charging cable. Contents of the Package listed above only, no other product is included. Note: Lighting effect in photographs may cause color to appear different from what it actually is. A margin of error of 1 to 3 cm in the measurements is possible.