28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8in diameter + Product Details Size –

+ Product Details Size – 10" x 32" or 32" x 10" is the size for the duct opening measurement only

+ Product Description Enhance your ventilation system with our high-quality grilles and registers

+ Product Details Size - 25"w X 8"h is the size for the duct opening measurement only

Easy clean Healthy air flow for your HVAC system - noise free components - no vibrating louvers etc

28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8in diameter + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 18" OR 18" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 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