24" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 14" Diameter + Product Details Size -

+ Product Details Size - 22"w X 12"h is the size for the duct opening measurement only

+ Product Details Size – 36"w X 22"h is the size for the duct opening measurement only

+ Product Details Size – 30" x 36" or 36" x 30" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 21

24" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 14" Diameter + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 24" x 36" OR 36" x 24" duct opening (measured at the opening), with actual outer dimensions of 26. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 23. 75" x 35. 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