30" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 18" Diameter actual front end outer dimensions

actual front end outer dimensions are approximately 22 5/8" width X 18 5/8" height

Actual Filter Size – 27 3/4"w x 11 3/4" x 1"

+ Product Details Size – 36"w X 10"h is the size for the duct opening measurement only

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

+ Product Details Size – 6" x 10" or 10" x 6" is the size for the duct opening measurement only

30" x 28" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 18" Diameter actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 30" x 28" OR 28" x 30" duct opening (measured at the opening), with actual outer dimensions of 32. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 29. 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