Honeywell POPUP2200 Pleated Filter Media. Replacement filter media fits Aprilaire or Space-Gard 2200 , 2120, 2250, Lennox PMAC20, GeneralAire AC-1. Approximately 20.25 x 24.25 x 5.87 Rated at MERV 11 This item ships collapsed and pops up when you open it. This enables them to be shipped for much less and take less space for storage.