â– Material:Galvanized steel sheet   â– Size ：Φ200，Φ250，Φ300,Φ350  â– Face Size（D）603×603，595×595 ( According to galvanized steel Stud ceiling size) â–  Accessories :C1 Radial Opposed Blade Damper  â–  Feature :Each layer of diffuser cone is mould pressed, no welding joint.â– Model DC is a round neck    square diffuser.  â– The DC round neck diffuser is fixed with a guide vane to provide uniform airflow over the surface of the diffuser face, the inverted hooks at the guide vane provides easy & convenient installation of flexible duct .