Accumulair Platinum 14x28x1 (13.5x27.5) MERV 11 Air Filter/Furnace Filters (6 pack) Nominal size 14 x 28 x 1, actual size measures 13.5 x 27.5 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 Merv 11 rating