18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe + Product Details Size -

+ Product Details Size - 8"w X 34"h is the size for the duct opening measurement only

+ Product Details Size – 16"w X 8"h is the size for the duct opening measurement only

The vent also has a bug screen to eliminate pest intrusion

actual front end outer dimensions are approximately 22 5/8" width X 30 5/8" height

Design – Easy unrestricted airflow for your HVAC system - 50° angled to provide maximum airflow

18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 28" OR 28" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 27. 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