36" x 20" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Copper Coil-Insulated Line Set + Product Details Size –

+ Product Details Size – 18" x 24" or 24" x 18" is the size for the duct opening measurement only

+ Product Details Size – 10" X 4" is the size for the duct opening (floor/vent hole) measurement only

no sharp edges

With its compact size and high-quality materials

36" x 20" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Copper Coil-Insulated Line Set + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 36" x 20" OR 20" x 36" duct opening (measured at the opening), with actual outer dimensions of 38. 5" W x 22. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 35. 75" x 19. 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