22" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible with Duct 8" Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 24" X 4" duct openings

+ Product Details Size - 4"w X 30"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 – 24"w X 18"h is the size for the duct opening measurement only

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

22" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible with Duct 8" Ideal for Walls & Ceilings:+ 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