AMCA Certified HVAC Damper BD-100 10x10 Galvanized Steel Air Flow Control

6 Inch Duct Manual Volume Backdraft Damper,FOR HVAC Vent Damper

4 Inch Galvanized Manual Volume Damper Sleeve for HVAC Duct Balancing Adjustable

Durable 5 Inch Galvanized Steel Backdraft Damper for HVAC Ventilation Systems

Ruskin 10x10x2 Volume Control Damper HVAC Air Flow Duct Damper – No Motor

5 Inch Duct Backdraft Damper Galvanized Steel One-Way Air Flow HVAC Damper

HVAC Duct Manual Volume Backdraft Damper 4 Inch Airflow Ducting Branch Vent

8" Galvanized Duct Volume Damper - Adjustable Airflow Control, HVAC Accessory