10" x 18" or 18" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 20.5"] w14h14 actual front end outer dimensions

actual front end outer dimensions are approximately 20 5/8" width X 32 5/8" height

+ Product Details Size - 20"w X 36"h is the size for the duct opening measurement only

+ Product Details Size – 24" x 26" or 26" x 24" is the size for the duct opening measurement only

+ Product Details Size – 12"w X 12"h

+ Product Details Size – 26"w X 12"h is the size for the duct opening measurement only

10" x 18" or 18" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 20.5"] w14h14 actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 10" x 18" or 18" x 10" duct opening (measured at the opening), with actual outer dimensions of 12. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 9. 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