16" x 28" or 28" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum Adjustable Curved Blade + Product Details Size –

+ Product Details Size – 16" x 18" or 18" x 16" is the size for the duct opening measurement only

actual front end outer dimensions are approximately 8

actual front end outer dimensions are approximately 27 5/8" width X 30 5/8" height

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Actual Filter Size – 33 3/4"w x 17 3/4" x 1"

16" x 28" or 28" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum Adjustable Curved Blade + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 16" x 28" OR 28" X 16" duct opening (measured at the opening), with actual outer dimensions of 18. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 15. 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