Eco-Aire 21x21x1 MERV 8, Pleated Air Filter, 21x21x1, Box of 6, Made in the USA Nominal: 21x21x1 or (21 x 21 x 1), Size: 20 7/8"x20 7/8"x3/4", AC Furnace Air Filter Made in the USA Designed to last up to 60 Days Comparable to the 3M Filtrete Dust and Pollen: Filtrete 600 Captures airborne particles between 3-10 microns in size