Air purifier features a three-in-one design for cleaner air quality and efficient air circulation for medium to large rooms. True HEPA filter captures 99.97 percent of airborne allergens, pollutants and gases. Ultraviolet LED light helps kill bacteria, viruses and germs to reduce contaminants. Carbon pre-filter helps reduce common household odors and 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.