20x25x5 (19.88x24.88x4.38) MERV 13 Aftermarket Honeywell&reg; Replacement Filter (2 Pack) Also can be used to replace collection cells in electronic models FC100C1017, F50A1066, F50E1141, Nominal size 20 x 25 x 5 (Actual size 20 x 24 3/4 x 4 3/8) This is an aftermarket filter High efficiency filter media collects small dust particles before they can collect on your coils. No assembly required...no combs needed...filter just slides right in!