12" x 8" or 8" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 14.5" X 10.5"] Aluminum Bar + Product Details Size –

+ Product Details Size – 32"w X 36"h is the size for the duct opening measurement only

+ Product Details Size - 24"w X 22"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 38 5/8" width X 10 5/8" height

+ Product Details Size - 34"w X 20"h is the size for the duct opening measurement only

14" Diameter Is The Size For The Duct Opening Measurement Only

12" x 8" or 8" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 14.5" X 10.5"] Aluminum Bar + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 8" or 8" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 10. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 7. 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