34" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Black 75"H – fits a 20"

75"H – fits a 20" X 18" duct opening

+ Product Details Size – 10"w X 12"h is the size for the duct opening measurement only

+ Product Details Size – 28" x 34" or 34" x 28" is the size for the duct opening measurement only

This simple adjustment reduces HVAC strain

6"w X 6"h Is The Size For The Duct Opening Measurement Only

34" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Black 75"H – fits a 20"+ 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