10" x 24" or 24" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 26.5"] Floor Grille + Product Details Size –

+ Product Details Size – 26"w X 8"h is the size for the duct opening measurement only

+ Product Details Size – 26" x 28" or 28" x 26" is the size for the duct opening measurement only

Ideal for Walls & Ceilings: Designed for seamless installation in standard 14" X 12" duct openings

actual front end outer dimensions are approximately 34 5/8" width X 16 5/8" height

10" x 24" or 24" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 26.5"] Floor Grille + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 10" x 24" or 24" x 10" duct opening (measured at the opening), with actual outer dimensions of 12. 5" W x 26. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 9. 75" x 23. 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