Accumulair Platinum 21x22x1 (Actual Size) MERV 11 Air Filter/Furnace Filters (6 pack) Actual Size Measures 21 x 22 x 0.75 Each filter lasts up to 3 months. Uniform pleat shape enhances dust holding capacity and maximizes air flow. Supercharged pleated panel filtering media ideally suited for capturing fine airborne allergens such as dust, smoke, dander, mold, pet dander, and dust mites - attracts particulates like dust to a TV screen. MERV 11 Rating