MicroAirScreen Adjustable Window Air Screen, 8 x 26'' - 48'' This Screen is 8'' high. Allows for an 8'' high opening. Adjustable for use in windows between 14''-24'' wide Originally designed for asthma and allergy sufferers, the MicroAirScreen is the most Advanced free flow window air filter available. The MicroAirScreen is a patented window microscreen that filters out environmental contaminants such as pollen and dirt, letting in sufficient quantities of clean air without the use of fans or blower The MicroAirScreen is a window air screen that filters out allergenic pollen and dirt giving clean ventilation to your home or office. It can be left in windows even in rain.