Have Multiple HVAC Systems That Need 14 x 30 x 1 Inch Furnace Filters? This is a box of 12 Safe Home TM Duo furnace filters that remove dust , pollen and odors from pets, chemicals, etc. Use if your furnace filter slot is one inch wide and takes a 14 inch by 30 inch by 1 inch furnace filter. Two layers of filtration are sandwiched around a metal frame so air leakage around the frame is stopped. The first white polyester layer removes dust, pollen and other particulates the second is an activated carbon filter. Use for furnace filter slots, temporary needs, or custom sizes in air return grills. The Duo replaces any 1 thick home air filter in any location and can last up to 3 months. Note Always check with your HVAC technician before changing from your current furnace filter. This unit is a MERV 8. Made in USA. How does the Duo work? The polyester outer layer removes 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. Safe Home Duo Filter Features Dimensions 14 x 30 x 1 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. Change each Duo at least every 3 months. Some conditions that feature pets, construction work, painting or smoking may produce more This item ships from a separate warehouse and may require extra time for delivery.