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] 6" Round Duct Pipe + Product Details Size - Suitable for all AC 8in diameter 12125SDCLNGBX

+ Product Details Size - 20"w X 2"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 27 5/8" width X 24 5/8" height

These are specially sized to fit into all drop ceilings

+ Product Details Size - 14"w X 36"h is the size for the duct opening measurement only

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] 6" Round Duct Pipe + Product Details Size Suitable for all AC 8in diameter 12125SDCLNGBX + Product Details Size 20"w X 2"h is the size for the duct opening measurement only actual front end outer dimensions are approximately 27 5 8" width X 24 5 8" height