This backdraft damper has a steel collar and has lightweight aluminum damper blades. It prevents air from coming back in. The damper blades are spring loaded.
A = 5 7/8 inches
B = 4 3/4 inches
Question: I have a cook top exhaust that is vertically going down (only have access to the vertical pipe run). Is there a backdraft damper that would work for that sort of installation? Answer: This 6 Inch Spring loaded Backdraft damper can be used with a cook top. Question: Can this damper be used in the vertical position? Answer: Yes.