Insulated fittings for flexible air ducts

An insulated tee-shaped fitting for a flexible air duct comprising, an inner tubular shell and an outer tubular shell shaped radially outwardly from the inner shell, a layer of insulation mounted within the space between the inner and outer shells, said inner shell providing a main conduit portion and a branch conduit portion extending normal to and communicating with the main conduct portion to thereby form said tee-shaped fitting, an end face extending between the inner and outer shells at the main conduit portion of said tee-shaped fitting, a retaining ring rotatably mounted on said inner shell adjacent said end face, a shoulder integral with the inner shell and engaging the retaining ring for holding the retaining ring thereon, the retaining ring being positioned between said end face and said shoulder, circumferentially spaced, radially outwardly extending keepers integral with one face of the retaining ring, a collar, a plurality of circumferentially spaced, radially inwardly extending keepers integral with the collar and cooperating with the keepers on the retaining ring, to thereby connect the collar to said retaining ring, the end portion of a flexible insulated air duct being secured to the inner shell at the main conduit portion of the tee-shaped fitting, said collar extending over the end of the air duct to cover the secured end portion, to thereby improve the appearance of the connection.