8" x 34" or 34" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 36.5"] Brown 6" width X 11

6" width X 11

4" X 10" Is The Size For The Duct Opening (floor/vent hole) Measurement Only

8-1/8"H x 4-5/8" W x 3-5/8"D

+ Product Details Size – 18"w X 32"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 10" x 34" or 34" x 10" duct opening (measured at the opening)

8" x 34" or 34" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 36.5"] Brown 6" width X 11+ Product Details Perfect Fit & Easy Sizing Designed for a 8" x 34" or 34" x 8" duct opening (measured at the opening), with actual outer dimensions of 10. 5" W x 36. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 7. 75" x 33. 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