Please notice that this air Monitors for indoor space, so please close the door & window before testing Or else the data may not be accurate We recommend using the Monitors and keep working for at least 60 minutes before reading the data Allows for better heat dissipation during operational, the device from getting hot, and more accurate measurement data It can accurately Monitors CO2, TVOC, HCHO, humidity temperature You can Monitors the environment at any time 1200mAh rechargeable battery Never be anxious about low power Equipped with a fast-responding and sensitive high-performances chip, the air Monitors can precisely captures the weak current generated during electrochemical reactions, Manufacturer: Mekalero