Galvanized Steel Outer / Male Connector for Joining Spiral Ducts 1.top quality,low price 2.prompt shipment ... Galvanized Steel Coupling Outer / Male Connector for Joining Spiral Ducts Purpose: HVAC, inlet and outlet of vent... Used ... in vemtilation system.Material: Galvanized Steel , Stainless Steel (With rubber /gasket & No rubber/gasket)Size: Dia.80, 100, 125, 150, 160, 180 ...