Our auto production line is special designed for Production Riveted-Type VCD Fire Damper frame. The air duct damper is an industrial plant civil construction of ventilation, generally used in ventilation system, to adjust the air flow manifold can also be used for new wind and back mix adjustment of the wind. If you are interesting this machine, pls feel free to contact with us! Jv@jack-aiva.Com / Whatsapp +86 13915206868