6" x 18" or 18" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 20.5"] sidewall + Product Details Size –

+ Product Details Size – 16"w X 12"h is the size for the duct opening measurement only

Actual Front End Outer Dimensions Are 12" Width X 4" Height - SEE IN DESCRIPTION HOW TO MEASURE A GRILLE

+ Product Details Size – 16"w X 22"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 26" x 32" OR 32" x 26" duct opening (measured at the opening)

R Value Rating of Insulation - R3

6" x 18" or 18" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 20.5"] sidewall + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 6" x 18" or 18" x 6" duct opening (measured at the opening), with actual outer dimensions of 8. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 5. 75" x 17. 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