Green Air Encore HEPA and Odor Fighting Filter Air Purifier with IonCluster Technology Three-stage advanced purifier system with True HEPA and Odor fighting filter technology. Non-Ozone based air purifier. IonCluster Technology to attack airborne microbes, purify the air, and aggressively kill bacteria Air quality color changing light ring and automatic air filter change indicator Four operating modes (AUTO, FAN, NIGHT, SILENT) Energy Efficient, Whisper Quiet Operation, Covers up to 1000 sq. ft.