€¢ Connects flexible foil and semi-rigid ducts €¢ Ideal for extending the exhaust collar of your clothes dryer €¢ Designed with one crimped end and one straight end €¢ Made of aluminum €¢ Not for in-wall use >> Dundas Jafine's family of Metal Duct Connectors are used to attach 2 pieces of flexible duct together. The 4 inch versions are also ideal for extending the exhaust collar."