Nominal Size: 14 x 25 x 1, Actual Size: 13 1/2 x 24 1/2 x 3/4 (13.5 x 24.5 x 0.75) Measure your air filter for the exact size and compare it to our actual size to ensure proper fit. Made with MERV rated synthetic poly blend 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 This dust reduction air filter is ideal in keeping your AC and furnace equipment working efficiently