8" x 36" or 36" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 38.5"] RV Mobile Home With a 6" diameter for

With a 6" diameter for the duct opening measurement

this model ensures top-notch air quality

+ Product Details Size - 4"w X 18"h is the size for the duct opening measurement only

Actual Filter Size – 27 3/4"w x 29 3/4" x 1"

8" x 36" or 36" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 38.5"] RV Mobile Home With a 6" diameter for+ Product Details Perfect Fit & Easy Sizing Designed for a 8" x 36" or 36" x 8" duct opening (measured at the opening), with actual outer dimensions of 10. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 7. 75" x 35. 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