20" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return grille + Product Details Size -

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

+ Product Details Size - 8"w X 26"h is the size for the duct opening measurement only

Design – Removable door/face for easy filter change & cleaning - uses a 1" thick filter

+ Product Details Size - 36"w X 10"h is the size for the duct opening measurement only

20" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return grille + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 20" x 24" OR 24" x 20" duct opening (measured at the opening), with actual outer dimensions of 22. 5" W x 26. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 19. 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