28" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Red Oak + Product Details Size –

+ Product Details Size – 8"w X 36"h is the size for the duct opening measurement only

+ Product Details Size - 28"w X 12"h X 2"d (for duct opening measurement only)

Actual Filter Size – 25 3/4"w x 19 3/4" x 1"

+ Product Details Size - 22"w X 32"h is the size for the duct opening measurement only

+ Product Details Size - 34"w X 32"h is the size for the duct opening measurement only

28" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Red Oak + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 8" OR 8" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 10. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 75" x 5. 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