8" X 4" [Duct Opening] 1-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 9.75"W X 5.75"H] 14" Diameter Actual Filter Size – 17

Actual Filter Size – 17 3/4"w x 31 3/4" x 1"

actual front end outer dimensions are approximately 20 5/8" width X 16 5/8" height

+ Product Details Size – 36"w X 12"h is the size for the duct opening measurement only

+ Product Details Size – 28"w X 28"h is the size for the duct opening measurement only

and with a built-in back 1/2" mesh they also protect you from annoying rodents like mice

8" X 4" [Duct Opening] 1-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 9.75"W X 5.75"H] 14" Diameter Actual Filter Size – 17+ Product Details Size 8"w X 4"h is the size for the duct opening measurement only, actual front end outer dimensions are 9. 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