12" X 8" [Duct Opening] 1-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 13.75"W X 9.75"H] Powder Coated actual front end outer dimensions

actual front end outer dimensions are approximately 28 5/8" width X 20 5/8" height

These Supply Diffusers with integral round necks are recommended for heating

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

Made of high quality aluminum that will never rust

12" X 8" [Duct Opening] 1-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 13.75"W X 9.75"H] Powder Coated actual front end outer dimensions+ Product Details Size 12"w X 8"h is the size for the duct opening measurement only, actual front end outer dimensions are 13. 75" width X 9. 75" height. Design Individually adjusting curved blades. Multi shutter damper with handle operator to adjust air flow. Screws Included High Quality Aluminum The premium durable aluminum will never rust and it will never wear through leaving the material with an elegant, beautiful, and smooth surface, adds a