Nominal Size: 20 x 20 x 1, Actual Size: 19 1/2 x 19 1/2 x 3/4 (19.5 x 19.5 x 0.75) Measure your air filter for the exact size and compare it to our actual size to ensure proper fit. Two beneficial air filters in one - MERV rated synthetic poly blend activated carbon infused pleated media Nordic Pure recommends changing 1" air filters every 30-90 days Made in the USA: Proudly manufactured in the USA, ensuring quality and supporting local production Ideal for customers who need odor control for pet and cooking smells