Honeywell MERV 8 Standard Air Cleaning 1" Filter, 20"L x 25"W x 1"H: * Captures a high percentage of household airborne particles, including microscopic particles you cannot see * 71 percent efficient at filtering large household air particles from the air * Filters pollen, household dust, airborne dust mite debris, mold spores, common allergens, clothing fibers and carpet fibers