24x24x4 Inch Air Pollution Furnace Filter With Twin Filter Media for HVAC Systems Safe Home TM DUO4-2424 is a powerful disposable air filter for maximum effectiveness at capturing allergens, odors, and chemicals from the air in your house. Note Check with your HVAC technician to verify that your system is able enough to handle the density of a MERV 8 filter before purchasing this or any other MERV 8 filter. Install this MERV 8 with Air Flow First Going through the White Media. Made in USA. Safe Home Duo4 Filter Features Dimensions 24 x 24 x 4 Captures up to 95% of common household allergens Eliminates odors from pets, paint, cooking, and more Uses high density carbon and advanced compounds FormaldaSorb TM , a patented potassium permanganate product plus the activated carbon in the second layer of the filter trap gasses that can cause health issues. Highly effective and affordable. MERV 8 polyester white ASHRAE rated allergen filter with industrial chemical and odor filter in media. Please measure carefully or choose a filter size and MERV rating identical to the one in your furnace. Units that are removed from wrappings or bent from being pushed into filter slots are not returnable . Product is not packaged for sale outside of the United States. Made in USA. Note This furnace filter is not a control device for radon, carbon monoxide or carbon dioxide. Limited Warranty Free of manufacturing and material defects. If product is found defective within 30 days of purchase, it will be replaced at no additional charge. Product is not packaged for sale outside of the United States. Use for furnace filter slots, temporary needs, or custom sizes in air return grills. The Duo4 replaces any 4 or 5 thick home air filter in any location and can last up to 9 months. Note All furnace filters with external frames are made slightly smaller than the noted dimensions in order to fit into the furnace filter slots. This is an industry standard. How does t This item ships from a separate warehouse and may require extra time for delivery.