SafeHome Internal Frame Dual Layer Furnace Filter Captures More For a cleaner, safer home , install a MERV 8 MERV=Minimum Efficiency Rating Value disposable twin layered Safe Home TM Duo furnace filter. 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. Disposable furnace filter captures dirt , dust, pollen and other allergens, odors, and harmful chemicals as small as 3.0 to 10 microns. Furnace air purifier filter fits a slot 20 x 25 x 1 inch. Duo air purifier filter with self sealing edges means no air gets around the filter. The Duo replaces a 1 thick home air filter and can last up to 3 months. Insert with air flow going first through the white layer. Safe Home Duo Filter Features Dimensions Fits 20 x 25 x 1 slot Captures up to 95% of common household allergens Eliminates odors from pets, paint, cooking, and more 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. 2 stage air filter one MERV 8 rated polyester white allergen filter plus the activated carbon filter pad. Made in USA. How does the Duo work? The polyester outer layers remove pollen, mold spores, and other common allergens. The inner layer features FormaldaSorb TM and activated carbon that traps a variety of odors and hazardous gasses, such as formaldehyde, ammonia, and others that are emitted by cleaning chemicals, paint, particle board, and other household items. No other filters are as effective at removing dust mites, mold spores, pollen, odors, cleaning chemicals, ozone, paint fumes, and common gasses like formaldehyde which triggers asthma and allergies. Change the Duo at least every 3 months. Some conditions that feature pet