30" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12in diameter 4" X 10" Is The

4" X 10" Is The Size For The Duct Opening (floor/vent hole) Measurement Only

actual front end outer dimensions are approximately 20 5/8" width X 36 5/8" height

10"w X 3"h Is The Size For The Duct Opening Measurement Only

or office environments

30" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12in diameter 4" X 10" Is The+ Product Details Perfect Fit & Easy Sizing Designed for a 30" x 18" OR 18" x 30" duct opening (measured at the opening), with actual outer dimensions of 32. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 29. 75" x 17. 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