Duct Corner: 1.material:Galvanized steel 2.size : can follow customer ... strong carton packingDelivery Detail:15 working daysspecification: TDC corner: For Transverse Duct Connector system, the flange is separately installed onto the ductwork ... , 2.5mm , 3.0mm , 3.5mm ,4.0mm appplication:used for fixed air diffusers or air hose air duct corner