34" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Copper Coil-Insulated Line Set only measure the "hole" in

only measure the "hole" in the wall/duct

actual front end outer dimensions are approximately 38 5/8" width X 18 5/8" height -

featuring a 8" round duct opening

controlled by a switch

12"w X 2"h Is The Size For The Duct Opening Measurement Only

34" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Copper Coil-Insulated Line Set only measure the "hole" in+ Product Details Perfect Fit & Easy Sizing Designed for a 34" x 6" Or 6" x 34" duct opening (measured at the opening), with actual outer dimensions of 36. 5" W x 8. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 33. 75" x 5. 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 Made