34" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter with filter actual front end outer dimensions

actual front end outer dimensions are approximately 36 5/8" width X 26 5/8" height

Think of the diameter as a straight line from one end to the other

See our separate listing for T-Bar supply grille

75"H – fits a 18" X 18" duct opening

+ Product Details Size - 4"w X 24"h is the size for the duct opening measurement only

34" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter with filter actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 34" x 24" Or 24" x 34" duct opening (measured at the opening), with actual outer dimensions of 36. 5" W x 26. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 33. 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