20x20x4 (19.5x19.5x3.75) MERV 11 Aftermarket Accumulair Replacement Filter MERV 11 Rating 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. Uniform pleat shape enhances dust holding capacity and maximizes air flow. Up to 30-times more efficient at capturing allergens than ordinary fiberglass filters. Manufactured by Accumulair.