Honeywell POPUP2200, 20 x 25 x 6 inches - MERV 11 Replacement Filter for Aprilaire, Space-Gard N/A Imported Self assembly for easy installation Highly Efficient - Rated at MERV 11 efficiency No combs, pleat spacers or end caps Used with SpaceGard 2200, 2120, 2250, Lennox PMAC20, GeneralAire AC-1, Aprilaire 2200 21"x 25"x 5" Unique design offers an additional 1" of filtration depth compared to standard cartridge replacement filters.