Eco-Aire 21 x 21 x 1 Premium MERV 8 Pleated Air Conditioner Filter, Box of 6 Eco-Aire filters not only improve your overall air quality but also protect your HVAC system by capturing dust and other airborne particles. Every Eco-Aire filter is produced in the USA using only the highest quality materials. These premium MERV 8 pleated filters utilize 100% synthetic media. They help capture airborne particles/allergens between 3-10 microns in size and are an ideal upgrade from standard disposable panel filters. These filters help fight dust, lint, pet dander, dust mites, and pollen. Eco-Aire Merv 8 filters are over 30-times more efficient at capturing micro particles than ordinary fiberglass filters.Nominal Size: 21x21x1 or (21 x 21 x 1), Actual Size: 20 7/8" x 20 7/8" x 3/4", AC and Furnace Air Filters