One(1) Window Screen Filter #1144 11″ Height – Adjusts to fit windows between 24″ and 44″ in width. Free Shipping The Safeguard Window Filter provides your home with fresh air all year long. The filter keeps out dust, dirt and is tested 94% efficient at keeping out ragweed pollen so you can enjoy fresh air without suffering from allergy symptoms. You’ll get a nice air exchange in the room without the wind. Even in inclement weather the Safeguard Window filter provides fresh filter air. Coated screen baffles keep out rain, snow, and wind*. These baffles slow down the air to increase the filters efficiency. The Safeguard Window Filter has a durable warp-proof, rust-proof aluminum frame. Built to last for years. Now with replaceable filter cartridges! The Safeguard Window Filter is available in sizes to fit most double-hung windows. Simply raise the bottom window, set the filter in place and adjust to the width of your window jamb, then lower the window to rest snugly on the frame. No tools necessary. The vinyl around the edges creates a tight seal. You can vacuum the white filter media with a hose attachment or blow it out to keep it clean. The screen filter should be replaced at least once per year. Replacement filters for Window Screen Filters are sold separately. *The Safeguard Window Filter will not work effectively in gale force winds, hurricanes, or tornadoes. The filter should be removed from your window in extreme weather conditions.