18" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Anodized Aluminum + Product Details Size –

+ Product Details Size – 16" x 24" or 24" x 16" is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 6" x 34" or 34" x 6" duct opening (measured at the opening)

+ Product Spec Sheet Floor Register Spec Sheet

+ Product Details Size - 18"w X 28"h is the size for the duct opening measurement only

Universal size

18" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Anodized Aluminum + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 10" OR 10" 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 9. 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