... etc. Duct connection: flange, Corner, G-clamp,corner,ect Octopus Metal Co., Ltd is the leading HVAC Ductwork manufacturer ... 4 efficient production sites for galvanized rectangular air duct manufacture. Our duct works are certified by China National Accreditation Service ... Transitions, Branches, Reducers etc.2)TDC duct connection: flange, Corner, G-clamp3)TDF duct connection: corner, cleat We offer ...