12" x 34" or 34" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Insulated Line Some of the best features

Some of the best features aren't readily apparent

actual front end outer dimensions are approximately 30 5/8" width X 18 5/8" height

actual front end outer dimensions are approximately 14 5/8" width X 20 5/8" height -

+ Product Details Size - 24"w X 10"h is the size for the duct opening measurement only

actual front end outer dimensions are 21

12" x 34" or 34" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Insulated Line Some of the best features+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 34" or 34" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 36. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 33. 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