10" x 30" or 30" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 32.5"] w18h18 + Product Details Size -

+ Product Details Size - 8"w X 30"h is the size for the duct opening measurement only

+ Product Spec Sheet Round Ceiling Diffuser Spec Sheet

featuring a sleek ½” fin design

actual front end outer dimensions are approximately 34 5/8" width X 20 5/8" height

10" x 30" or 30" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 12.5" X 32.5"] w18h18 + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 10" x 30" or 30" x 10" duct opening (measured at the opening), with actual outer dimensions of 12. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 9. 75" x 29. 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