DuPont Platinum Max Allergen Air Filter, 20x24x1, MERV 12, 4-Pack Electrostatic air filter provides maximum coverage in capturing allergen and microscopic airborne particles Anti-microbial protection fights odor causing microbes on filter surface and optimizes the filter life Contains Oguard additives which have been shown to have efficacy on a broad range of household odors DuPont air-furnace pleated filters lasts up to 90 days Minimum efficiency reporting value or MERV rating is 12, Laboratory Tested