Amazon.com: BestAir A201-SGM-BOX11R Air Cleaning Furnace Filter with Cardboard Frame, MERV 11, For Aprilaire/SpaceGard 2200, 2250 (201) & Lennox PMAC-20C 24", 20" x 25" x 6", Single Pack, 1 Count (Pack of
Amazon.com: Aprilaire 201 Replacement Filter (Pack of 2) : Home & Kitchen
Aprilaire 201 Filter for 2200 and 2250 Air Purifiers
AprilAire 201 Air Filter Performance Upgrade Kit (1213) - 65% More Eff