6" x 28" or 28" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 30.5"] w18h18 Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 16" X 4" duct openings

Design – Individually adjusting curved blades

Actual Filter Size – 25 3/4"w x 11 3/4" x 1"

+ Product Details Size – 26"w X 28"h is the size for the duct opening measurement only

6" x 28" or 28" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 30.5"] w18h18 Ideal for Walls & Ceilings:+ Product Details Perfect Fit & Easy Sizing Designed for a 6" x 30" or 30" x 6" duct opening (measured at the opening), with actual outer dimensions of 8. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 5. 75" x 29. 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