36" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Supply Grille Actual Filter Size – 7

Actual Filter Size – 7 3/4"w x 9 3/4" x 1"

+ Product Details Size – 36"w X 16"h is the size for the duct opening measurement only

Carefully shrink wrapped with cardboard backing to prevent damage in shipment

if your hole is 20" wide by 14" tall

36" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Supply Grille Actual Filter Size – 7+ Product Details Perfect Fit & Easy Sizing Designed for a 36" x 18" OR 18" x 36" duct opening (measured at the opening), with actual outer dimensions of 38. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 35. 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