16" x 18" or 18" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter fixed bar + Product Details Size -

+ Product Details Size - 20"w X 30"h is the size for the duct opening measurement only

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

+ Product Details Size – 12" x 14" or 14" x 12" is the size for the duct opening measurement only

+ Product Details Size – 28"w X 10"h is the size for the duct opening measurement only

+ Product Details Size - 6"w X 24"h X 2"d (for duct opening measurement only)

16" x 18" or 18" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter fixed bar + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 16" x 18" OR 18" X 16" duct opening (measured at the opening), with actual outer dimensions of 18. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 15. 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