Nordic Pure 18x20x1PureGreen-6 AC Furnace Air Filters, 6-Piece Actual Size of Air Filter: 17 1/2 x 19 1/2 x 3/4 (17.5 x 19.5 x 0.75) inches Made from an environmentally responsible non-woven, high loft, antimicrobial filter media All Nordic Pure air filters are electrostatically charged for maximum performance MERV 6 rating minimizes energy consumption while maintaining a high dust holding capacity Made in the USA