20" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Insulated Line + Product Details Size -

+ Product Details Size - 4"w X 34"h is the size for the duct opening measurement only

Pre-flared ends with nuts are for simple and easy installation

Actual Filter Size – 19 3/4"w x 25 3/4" x 1"

+ Product Details Size - 25"w X 28"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 28 5/8" width X 30 5/8" height

20" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Insulated Line + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 20" x 10" OR 10" x 20" duct opening (measured at the opening), with actual outer dimensions of 22. 5" W x 12. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 19. 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