Aerostar 18x20x2 MERV 11, Air Filter, 18x20x2, Box of 4

Change frequency 60-90 days, Made in the USA.. Size: 17 1/2"x19 1/2"x1 3/4", Nominal: 18 x 20 x 2 18x20x2, AC Furnace Air Filter Comparable to 3M Filtrete MPR 1000 to 1200 Micro Allergen Defense Comparable to Honeywell Allergen Plus FPR 7 Fights lint, dust mites, mold spores, pollen, pet dander, dust, and smoke