12" X 8" [Duct Opening] 3-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 13.75"W X 9.75"H] w26h26 actual front end outer dimensions

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

Its generous size and universal design ensure a perfect fit for a wide range of thermostat models

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

our damper is designed to perfectly align with your setup

Crafted from robust 20-gauge steel

12" X 8" [Duct Opening] 3-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 13.75"W X 9.75"H] w26h26 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