Aerostar 21 1/2x21 1/2x1 MERV 13, Pleated Air Filter, 21 1/2 x 21 1/2 x 1, Box of 4, Made in The USA
- Nominal: 21 1/2 x 21 1/2 x 1, Size: 21 1/2\"x21 1/2\"x3/4\" 21 1/2x21 1/2x1, AC Furnace Air Filter
- Comparable to 3M Filtrete MPR 1500 to 1900 Ultimate Allergen Defense
- Comparable to Honeywell Allergen Elite FPR 10
- Fights lint, dust mites, mold spores, pollen, pet dander, fine dust, smoke, viruses, and bacteria.
- Change frequency 60-90 days, Made in the USA.