Nordic Pure 20x25x5, MERV 10, Lennox Replacement Air Filter, Box of 1 Actual Size: 19-5/8 x 19-7/8 x 4-3/8 Replacement filter for Honeywell FC100A1011, 203721, FC35A1019 Electrostatic air filter captures dust, pollen, dust-mite debris, mold spores, pet dander, and smog Hypoallergenic and antimicrobial pleated electrostatic filter material Made in the USA