TrueCLEAN™ enhanced air cleaner for use in return air ducts of forced air systems provides high-filtration performance while destroying contaminants, treating air stream through three-step process: charge, capture, and destroy. Duct mounted. Dimensions: 20x20 inches (508x508mm); airflow capacity (Cubic Feet/Minute-CFM): maximum-- 1800 CFM; airflow capacity (Cubic Meters/Hour-m³/hr.): maximum-- 3060 m³/hr.; Minimum Efficiency Reporting Value (MERV)-15. Efficiency ranges are defined for small particles, E1 = 0.3 to 1.0 microns; medium particles, E2 = 1.0 to 3.0 microns; and large particles, over 3.0 microns. Fractional efficiency: E1=90%, E2=96%, E3=99%. Replacement filters: FR8000A2020. Frequency: 60 Hz.