12" X 4" [Duct Opening] 1-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 13.75"W X 5.75"H] w10h10 these heavy-duty louvers are ideal

these heavy-duty louvers are ideal for use in attics

Easy Installation – Includes all necessary screws for quick and hassle-free setup

Actual Filter Size – 47 3/4"w x 23 3/4" x 1"

+ Product Details Size – 18" Corner Baseboard Grille - White - HVAC corner vent cover

12" X 4" [Duct Opening] 1-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 13.75"W X 5.75"H] w10h10 these heavy-duty louvers are ideal+ Product Details Size 12"w X 4"h is the size for the duct opening measurement only, actual front end outer dimensions are 13. 75" width X 5. 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