Hyjoy 4-Inch Ventilation Damper Set, 10 Units, Backdraft Shutter for Plastic One-Way Airflow Duct, Inline Fan Vent Deflector HVAC Exhaust Connector

Back draft damper for insertion into 4" inch ventilation ducts. The backflow damper opens and closes automatically. It is sturdy and can be installed either horizontally or vertically. The flap is suitable for retrofitting, as it fits completely inside the duct. Designed to back draught and connections between Plastic Ducting and Flexible Ducting. Intended for use in AC , dryer vents, exhausts, extractors or hoods, heating units, fans, vents, and other residential and industrial HVAC applications. with VENT HVAC components. Duct draft stopper prevents air or wind from entering the ventilation pipe. In this setup, the flap is installed so that the flap leaves only open in the outgoing air direction. This ensures that no air / wind or odor can enter the ventilation pipe from outside. Installation involves pushing the unit into the ventilation pipe until it stops. The damper should be when installed horizontally to allow optimal opening and . This principle also applies to vertical installation.