36" x 20" Cube Core Eggcrate Return Air Filter Grille for 1" Filter flat stamped steel + Product Details Size –

+ Product Details Size – 14" x 34" or 34" x 14" is the size for the duct opening measurement only

Ideal for Walls & Ceilings: Designed for seamless installation in standard 18" X 18" duct openings

Actual Filter Size – 33 3/4"w x 23 3/4" x 1"

+ Product Details Size - 24"w X 2"h is the size for the duct opening measurement only

36" x 20" Cube Core Eggcrate Return Air Filter Grille for 1" Filter flat stamped steel + 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