Breathe easy with the Hunter Fan Company HP400 Round Tower Air Purifier. This sleek cylindrical room air purifier features True HEPA filtration and an EcoSilver pre-filter to eliminate allergens and other airborne pollutants providing clean and healthy air in your home or office. The EcoSilver pre-filter technology helps to prevent the growth of microorganisms while the True HEPA filter captures up to 99.97% of particles as small as 0.3 microns. With a filter replacement indicator you ll never forget when it s time for a filter change ensuring your air purifier for dorm always runs at maximum efficiency.