8" X 8" [Duct Opening] 4-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 9.75"W X 9.75"H] 12" Round Duct Pipe + Product Details Size – 4 X 12 Is CRFG2028 Width_14in

+ Product Details Size – 8"w X 20"h is the size for the duct opening measurement only

+ Product Details Size – 34"w X 32"h is the size for the duct opening measurement only

If your hole is 14" wide by 20" tall

+ Product Details Size – 10"w X 24"h is the size for the duct opening measurement only

The total outer size of this grille is the listed size plus 3"

8" X 8" [Duct Opening] 4 Way Air Vent Adjustable Aluminum Curved Blades Integral Multi Shutter Damper HVAC Diffuser [Outer Dimensions: 9.75"W X 9.75"H] 12" Round Duct Pipe + Product Details Size – 4 X 12 Is CRFG2028 Width_14in + Product Details Size – 8"w X 20"h is the size for the duct opening measurement only + Product Details Size – 34"w X 32"h is the size for the duct opening measurement only