12" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w24h24 + Product Details Size -

+ Product Details Size - 25"w X 8"h is the size for the duct opening measurement only

+ Product Details Size - 20"w X 28"h is the size for the duct opening measurement only

while the ingenious dial-controlled damper empowers you to effortlessly regulate airflow using your foot

and its seamless drop-in installation process ensures effortless setup

please note that the total outer dimensions of the grille measure 6" in diameter

12" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w24h24 + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 24" or 24" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 26. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 23. 75" x 1" Premium Airflow Efficiency High performance cube core eggcrate design allows 95% airflow efficiency, reducing energy costs and maximizing HVAC system lifespan. Durable, Rust Free Aluminum