12" x 28" or 28" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter ceiling Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 24" X 6" duct openings

as the multidirectional design ensures consistent temperature control

actual front end outer dimensions are approximately 26 5/8" width X 10 5/8" height

+ Product Details Outer dimensions: – fits a duct opening

+ Product Details Size – 20"w X 12"h is the size for the duct opening measurement only

12" x 28" or 28" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter ceiling Ideal for Walls & Ceilings:+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 28" or 28" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 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