QWORK Draft Blocker 4 Inch Damper Stopper Duct Damper Backflow Preventer Inline Built-in Fan Vent Ventilation Vent Deflector, 2 Pack

QWORK Draft Blocker 4 Inch Damper Stopper Duct Damper Backflow Preventer Inline Built-in Fan Vent Ventilation Vent Deflector, 2 Pack

Design:The valve can opens and closes smoothly at low airflow, featuring a smooth-operating spring and an internal foam strip to prevent the cutter from rattling. Feature: Backdraft damper designed for installation in inch-sized ventilation ducts. The damper automatically opens and closes, equipped with a robust spring mechanism. It is versatile for horizontal or vertical mounting. The flip-up cover is ideal for retrofitting as it fits entirely within the duct. Instruction: Install by inserting it into the vent pipe until it stops. The spring should be positioned horizontally for horizontal installation so that it can optimally open and close. Install the return louvers with the damper blades open in the outlet direction only. Application: Return air valves can be inserted into flexible or non-flexible ventilation ducts. Perfect for air conditioners (AC), dryers, exhaust units, hoods or range hoods, heating ducts, vents and other HVAC applications. They cannot be used with plastic ducting because of the difference in size. 100% Satisfied Service: Enjoy a smooth & frustration free experience. QWORK