The perfect companion for indoor environments, allowing you to monitor CO2 levels, temperature, relative humidity, and atmospheric pressure in real-time | Easy for anyone to use - the color coding and the optional buzzer warns you when the CO2 concentration gets too high | Power-efficient e-ink display ensures super long battery life for this wireless device (up to 4 years) | Smartphone app for viewing and analyzing historical data up to 14 days history (supports iPhone and iPad with iOS 12 or later, Android devices with Oreo 8.0 or later, compatible with Bluetooth 4.1 or later) | Uses nondispersive infrared sensor (NDIR) technology for most precise and reliable CO2 measurements