14" x 28" or 28" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return grille Ideal for Walls & Ceilings:

Ideal for Walls & Ceilings: Designed for seamless installation in standard 18" X 12" duct openings

Width vs Height:

+ Product Details Size – 30"w X 10"h is the size for the duct opening measurement only

+ Product Details Size - 20"w X 12"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 14 5/8" width X 38 5/8" height -

14" x 28" or 28" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return grille Ideal for Walls & Ceilings:+ Product Details Perfect Fit & Easy Sizing Designed for a 14" x 28" OR 28" X 14" duct opening (measured at the opening), with actual outer dimensions of 16. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 13. 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