Abstract: A coupling for a ventilation duct assembly for use with interconnecting ventilation duct elements and method of assembly is disclosed comprising a first and a second ventilation duct element formed from a flexible panel shaped and foldable into a ductwork element with a male end smaller in diameter than a female end and with an abutment for restricting movement of the female end over the male end of an adjacent ductwork element. A C-shaped collet is also provided and shaped to fit over the interconnecting male and female ends of the formed ductwork elements for interconnection of adjacent shaped ductwork elements, and sized to extend between adjacent slideable locking elements from corresponding adjacent shaped ductwork elements.