12" x 30" or 30" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter white + Product Details Size –

+ Product Details Size – 34" x 34" is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 26" x 12" OR 12" x 26" duct opening (measured at the opening)

actual front end outer dimensions are approximately 20 5/8" width X 32 5/8" height

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 12" OR 12" X 18" duct opening (measured at the opening)

actual front end outer dimensions are approximately 24 5/8" width X 27 5/8" height

12" x 30" or 30" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter white + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 30" or 30" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 29. 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