oval air duct, circular air duct,air pipe,pipe fittings, bend, louver, elbow We supply spiroduct made ... and offshore.If you need bend, louver, elbow, connection, fire damper, VCD, ventilator, fans, please contact us for offer and product ... .We manufacture all the duct and duct fiitings in our own factory, that means we can give you a fast delivery. Circular Air Duct