Butterfly Damper Butterfly Damper are used in Round duct where to prevent back flow of air. It acts are NRV in ducts Truestar butterfly damper have two flap of GI sheet which are operated by gear arrangment. Butterfly Damper OUR PRODUCTS The damper can be open and close by screw.Model:- TSAS-BFDConstruction:-Blade:- GI sheet of 18 gauge Gear assembly:- 20 Gauge GIFinish:- Mill finish https://truestarairsystems.com/index.php/butterfly-damper/All Rights Reserved