Air purifier features a three-in-one design for cleaner air quality & efficient air circulation for medium to large rooms. True HEPA filter captures 99.97 percent of airborne allergens, pollutants & gases. Ultraviolet LED light helps kill bacteria, viruses & germs to reduce contaminants. Carbon pre-filter helps reduce common household odors & captures larger particles to keep your HEPA filter running efficiently. Low-noise technology operates at just 32 decibels to prevent distractions in low-noise environments. Blue indicator light flashes when a filter replacement is required as a helpful reminder.