6" x 16" or 16" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 18.5"] RV Mobile Home Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 12" X 4" duct openings

actual front end outer dimensions are approximately 20 5/8" width X 22 5/8" height -

+ Product Details Size – 4"w X 12"h is the size for the duct opening measurement only

Designed for a 1" thick filter

6" x 16" or 16" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 18.5"] RV Mobile Home Ideal for Walls & Ceilings:+ Product Details Perfect Fit & Easy Sizing Designed for a 6" x 16" or 16" x 6" duct opening (measured at the opening), with actual outer dimensions of 8. 5" W x 18. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 5. 75" x 15. 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