8" x 6" or 6" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 8.5"] w10h10 + Product Details Size -

+ Product Details Size - 28"w X 8"h is the size for the duct opening measurement only

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

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4" X 12" Is The Size For The Duct Opening (floor/vent hole) Measurement Only

[Outer Dimensions: 16

8" x 6" or 6" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 8.5"] w10h10 + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 8" x 6" or 6" x 8" duct opening (measured at the opening), with actual outer dimensions of 10. 5" W x 8. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 7. 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 Made