Abstract: A connector member for coupling flexible cylindrical tubular duct to the wall of a fibrous duct is comprised of a pair of parallel metal strips, the opposed marginal edges of which are connected to a flexible central strip. A clamp and a slip joint are provided on the respective strips for maintaining the metal strips in a cylindrical configuration, with the ends of the strips overlapping. One said strip including outwardly facing gaskets disposed at opposite sides of the wall of the fiber duct, the other strip including an inwardly facing gasket clamped about the flexible cylindrical ducting.