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] Compatible with Duct 6" actual front end outer dimensions 4 X 12 Is CRFG2028 Width_14in

actual front end outer dimensions are approximately 27 5/8" width X 30 5/8" height

+ Product Details Size – 20"w X 14"h is the size for the duct opening measurement only

+ Product Details Size – 24"w X 36"h is the size for the duct opening measurement only

Actual Filter Size – 21 3/4"w x 35 3/4" x 1"

actual front end outer dimensions are approximately 34 5/8" width X 30 5/8" height

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] Compatible with Duct 6" actual front end outer dimensions 4 X 12 Is CRFG2028 Width_14in actual front end outer dimensions are approximately 27 5 8" width X 30 5 8" height + Product Details Size – 20"w X 14"h is the size for the duct opening measurement only