Nominal size: 20 x 24 x 1, actual size: 19 3/8" x 23 3/8" x 3/4" comparable to 3m filtrete mpr 600 clean living comparable to honeywell micro defense plus fpr 5 fights lint, dust mites, mold spores, pollen, pet dander, and dust. change frequency 60-90 days, made in the usa.
