HDX 20 in. x 25 in. x 4 in. Honeywell Replacement Pleated Air Filter FPR 9, MERV 13 HDX-HW2025-13-3 - The Home Depot
Amazon.com: Honeywell Home 20x25x4 MERV 12, AC Furnace Air Filter, 3 PACK (CF200A1016-3PKAM) (Actual Dimensions: 18.84 x 24.75 x 4.38 in.) : Everything Else
20x25x4 Air Filter MERV 13 Glasfloss Replacement for Honeywell - Box of 5