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"] Color_Red Oak Wood + Product Details Size –

+ Product Details Size – 16"w X 30"h is the size for the duct opening measurement only

guaranteeing efficient ventilation throughout your space

+ Product Details Size - 18"w X 8"h is the size for the duct opening measurement only

Actual Filter Size – 35 3/4"w x 33 3/4" x 1"

and keep the cold air out during the Winter Months

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"] Color_Red Oak Wood + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 6" x 28" or 28" x 6" duct opening (measured at the opening), with actual outer dimensions of 8. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 5. 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 Made