Bacharach 1580-8001 Comfort Chek 400 Portable Air Quality Monitor.

The Comfort Chek 400 is an economical, easy-to-use indoor air quality (IAQ) monitor from Bacharach, engineered with three sensors that simultaneously measure and record temperature, relative humidity, and carbon dioxide (CO2) levels in the air. The large LCD displays all three sensor readings as well as battery status and is backlit for easy readability in dark environments. The Comfort Chek™ 400 can operate up to 24 hours with alkaline batteries, or the supplied wall adapter is ideal for around the clock air quality monitoring in office environments, schools, hotels or other public buildings.