Using air semiconductor sensor , PM2.5 sensor and electrochemical sensor , high-performances chip , detection is more accurate , high accuracy , and the accuracy can reach 1PPM 9 in 1 : Multifunctional air detectors of CO2 concentration , COconcentration , TVOC value , HCHO value , PM2.5 / PM10 value , temperature and relative humidity Large digital screen with backlights , clear and easy to read , alarm function Equipped with 2000mAh high-capacity rechargeable battery , low power consumption and long endurances , no need to replace the battery frequently Suitable for , school , warehouse , agricultural plantings , No need to calibrate at starting , automatic, Manufacturer: Watreketal