Dual Allergen VOC Furnace Filter Lets No Air Past to Return to Your Home 19 inch by 22 inch by 1 inch MERV 8 air purifier furnace filter with two filters and self-sealing edges due to its internal frame! The Safe Home TM Duo is the only home air replacement filter that captures allergens, odors, and harmful chemicals and fits in a standard one inch furnace panel slot or a return air grille with removable face for filter insert. 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. 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 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 othersthat 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. This item ships from a separate warehouse and may require extra time for delivery.