18" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Red Oak 75"H – fits a 12"

75"H – fits a 12" X 10" duct opening

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

+ Product Details Size - 20"w X 24"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 24" x 8" OR 8" x 24" duct opening (measured at the opening)

or commercial environment

18" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Red Oak 75"H – fits a 12"+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 8" OR 8" X 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 10. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 7. 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