This disposable deep pleated air filter cartridge is specially designed to work in a Honeywell whole-house air cleaner. The filtering medium is made with synthetic mechanical filtering fibers. The medium is adhered to an expanded metal backing, deep pleated and encased in a moisture resistant kraft board frame. It offers a MERV 8 level of performance. 20" x 25" x 4-1/2" High efficiency residential air cleaner cartridge Electrostatically charged media Fits honeywell F25 media air filter 203719 MERV rating 8 Lasts up to 1 year Effective against pollen, dust/lint, dust mite debris, pet dander, mold, bacteria, virus carriers.