18" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 2-Way Deflection + Product Details Size -

+ Product Details Size - 18"w X 16"h is the size for the duct opening measurement only

Red Oak Wood – A true decour upgrade to you HVAC application - adds a touch of warmth & softness to the room

Design – Cubic core eggcrate design Offers highest airflow efficiency at almost 95%

With a 5" diameter for the duct opening measurement

18" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 2-Way Deflection + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 20. 75" x 20. 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 from