18" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w6h6 + Product Details Size -

+ Product Details Size - 16"w X 30"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 20 5/8" width X 22 5/8" height -

5" - SEE BELOW IN DESCRIPTION HOW TO MEASURE A GRILLE

+ Product Details Perfect Fit & Easy Sizing - Designed for a 24" x 10" OR 10" x 24" duct opening (measured at the opening)

Premium Plated Finish and Modern Contempo Design Forming a Luxurious Piece

18" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w6h6 + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 36" OR 36" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 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