The Hunter Air Purifier is 99.97% effective at removing particles as small as 0.1 Microns that pass through the filter. Overall airborne particle retention in any environment depends upon a number of factors including the amount of air processed, the particle type, and the rate of particle introduction into the environment. Features: HEPAtech 99.97% Effective to 0.1 Microns. Changes the Air up to 6 Times Per Hour. 30% Better Odor Reduction. Mechanical Filter Change Indicator. 3-Speed Whisper-Quiet Hunter Fan. Specifications: Room Size - 12 inch x 12 inch. Cubic Feet Per Minute - 200.