Nominal Size: 12 x 24 x 1, Actual Size: 11 1/2 x 23 1/2 x 3/4 (11.5 x 23.5 x 0.75) Measure your air filter for the exact size and compare it to our actual size to ensure proper fit. MERV rated synthetic poly blend pleated media plus activated charcoal flat panel added to increase odor control 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 looking for superior filtration capturing fine particles, including coughs & sneezes, smog and smoke, but also needing an odor control element