10" x 8" or 8" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 10.5"] steel + Product Details Size -

+ Product Details Size - 26"w X 30"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 16" x 18" OR 18" X 16" duct opening (measured at the opening)

75"H – fits a 12" X 4" duct opening

actual front end outer dimensions are approximately 26 5/8" width X 24 5/8" height

Solid Base Construction – Features a solid base for stable installation and reliable protection

10" x 8" or 8" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 10.5"] steel + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 10" x 8" or 8" x 10" duct opening (measured at the opening), with actual outer dimensions of 12. 5" W x 10. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 9. 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 Made