Original 21.5″ X 27″ X 5″ MERV 11 Honeywell Filter. (Actual Dimensions – 21 1/2″ X 27 1/2″ X 4-3/8″). Highly-efficient, synthetic material features extended surface pleats that have a higher dirt-holding capacity than competitive filters. These high quality filters capture and hold pollutants inside the filter, allowing clean air to flow freely through the system. FEATURES: Factory original product from Honeywell Moisture resistant frame remains sturdy even in high humidity Rust resistant galvanized wire downstream gives the filter rigidity and holds media in place after installation Built-in support fingers hold pleats in place and allow for maximum dust holding For optimum system performance, replace the filter every six months MERV 10 rating means the filter attracts common large household allergens like dust, pollen, and mold spores as well as smaller particulate Fits Honeywell Series: F27F Replaces: 207583