Change frequency 60-90 days, Made in the USA.. Nominal Size: 16 1/4 x 21 1/2 x 1, Actual Size: 16 3/8" x 21 1/2" x 3/4" 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
