4-STAGE AIR PURIFICATION: Cleans the air in four stages using an active carbon pre-filter, a True HEPA filter, a UV-C light with photocatalyst filter, and an ionizerSMART AIR QUALITY MONITOR: Displays air quality using a color-coded lighting system, then automatically adjusts fan speed to achieve clean air in medium to large rooms up to 190 square feet and larger3-SPEED FAN: Offers adjustable low, medium, and high settings to let you choose based on the needs of the roomFILTER RESET INDICATOR: Lets you know when it's time to change the Active Carbon Pre-Filter and True HEPA Filter