34" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Return + Product Details Size –

+ Product Details Size – 22"w X 6"h is the size for the duct opening measurement only

+ Product Details Size - 18"w X 36"h is the size for the duct opening measurement only

+ Product Details Size - 12"w X 16"h is the size for the duct opening measurement only

Actual Filter Size – 31 3/4"w x 15 3/4" x 1"

+ Product Details Size – 10" x 30" or 30" x 10" is the size for the duct opening measurement only

34" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Return + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 34" x 36" OR 36" x 34" duct opening (measured at the opening), with actual outer dimensions of 36. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 33. 75" x 35. 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