12" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 14.5" X 14.5"] ceiling + Product Details Size -

+ Product Details Size - 26"w X 8"h is the size for the duct opening measurement only

R value rating of insulation - r3

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+ Product Details Size - 8"w X 22"h is the size for the duct opening measurement only

12" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 14.5" X 14.5"] ceiling + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 11. 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 from