Material:  Galvanized Steel Sheet
Size(W×H): According to air duct sizes 
Feature: 
Usually,it is open, when the air flow temperature in the air duct get ting up to 70℃, then the fuse acts, and the damper is automatically closed.
Manual Open or close is available, and manually reset the damper after the damper acting.
The damper has six gears of regulatng air volume damper.
Once the damper is closed, outputs the close electric signal (DC24V).