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] w18h18 Constructed from sturdy 20-gauge steel

Constructed from sturdy 20-gauge steel

Designed with a ring base for flexible installation

Actual Filter Size – 11 3/4"w x 27 3/4" x 1"

One model suits both T-Bar and Drywall installations

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] w18h18 Constructed from sturdy 20-gauge steel+ 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