36" x 34" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w30h30 + Product Details Size –

+ Product Details Size – 8" x 24" or 24" x 8" is the size for the duct opening measurement only

+ Product Details Size - 34"w X 12"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 16" x 12" OR 12" X 16" duct opening (measured at the opening)

+ Product Details Size – 10" x 12" or 12" x 10" is the size for the duct opening measurement only

36" x 34" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w30h30 + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 36" x 34" OR 34" x 36" duct opening (measured at the opening), with actual outer dimensions of 38. 5" W x 36. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 35. 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