18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Width_20in 16" x 3" Aluminum Spiral

16" x 3" Aluminum Spiral Duct Air Vent Grille Cover - Fully Adjustable Double Deflection HVAC Air Supply

+ Product Details Size – 12"w X 26"h is the size for the duct opening measurement only

10" x 6" Decorative Wood Air Vent HVAC Duct Cover Grille - Polished Finish Red Oak Wood - 2-Way Air Direction

+ Product Spec Sheet Extruded Aluminum Ceiling Diffuser Spec Sheet

18" x 28" or 28" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Width_20in 16" x 3" Aluminum Spiral+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 28" OR 28" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 27. 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