Back Draft Damper-Vertical
Is a Backdraft Damper Designed for Vertical Operation.
Backdraft Damper-Horizontal
Is a Backdraft Damper Designed for Horizontal Operation.
Backdraft Dampers with Flanges
Is a Backdraft Damper Designed for Vertical or Horizontal Operation but can have different size Flanges on the Front or the Back of the Damper for ease of Installation.