The Extech CO220 Desktop Indoor Air Quality CO2 Monitor is perfect for monitoring the air quality and ensuring proper air ventilation in conference rooms, schools, greenhouses, factories, hotels, hospitals, and anywhere else that have high levels of carbon dioxide. The display enables the user to see clearly carbon dioxide levels, humidity, air temperature, and even tells the date and time. Readings made by the Extech CO220 can be stored, and up to 99 readings may be stored/recalled.