Unique Bargains - 3" HVAC Duct Damper, 2pcs Manual Volume Backdraft Damper Metal Adjustment Airflow Ducting Control Valve - Silver

HVAC duct manual air volume control valve is used to adjust and control the air volume in heating, ventilation, and air conditioning systems. To adjust the air volume in the HVAC system and balance the air flow distribution, thereby improving the energy efficiency of the system to a certain extent.