12" x 10" or 10" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 14.5" X 12.5"] 10" Round Duct Pipe + Product Details Size –

+ Product Details Size – 40"w X 10"h is the size for the duct opening measurement only

Actual Filter Size – 19 3/4"w x 29 3/4" x 1"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 30" or 30" x 8" duct opening (measured at the opening)

actual front end outer dimensions are approximately 14 5/8" width X 38 5/8" height -

Easy clean Healthy air flow for your HVAC system - noise free components

12" x 10" or 10" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 14.5" X 12.5"] 10" Round Duct Pipe + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 10" or 10" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 12. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 9. 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