The 16 in 1 Air Quality Monitor is an indoor unit with a 7" display that provides real-time readings of 9 AQI and 7 AQI alerts. It features electrochemical, metal oxide, and optical sensor types for accurate measurements. The device is sealed and comes with 1 D batteries included, making it convenient for on-the-go use. Its compact size and lightweight design make it easy to transport and use in various settings, providing a comprehensive analysis of indoor air quality. never been used.