22" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible with Duct 8" + Product Details Size -

+ Product Details Size - 6"w X 8"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 24" x 6" OR 6" x 24" duct opening (measured at the opening)

+ Product Details Size – 12" x 12" is the size for the duct opening measurement only

+ Product Details Size – 24"w X 18"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 26" x 26" duct opening (measured at the opening)

22" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible with Duct 8" + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 22" x 28" OR 28" x 22" duct opening (measured at the opening), with actual outer dimensions of 24. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 21. 75" x 27. 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