The joiner is used to link standard 6 00mm straight ducting with any duct components. It provides a smooth & strong joint. Typical other components are: horizontal elbows and 600mm to 300mm reducers etc.; which require a joiner at each interface. T he joiner is first fitted to the squ are ends of adjacent 600mm duct (or components) and 6 x Ø 8 mm holes are drilled through both duct sides and ends, matching the holes in the joiner. Then a small Ø 8 mm screw rivet (supplied) is inserted in each hole. The end of the screw rivet expands to ma ke a mechanically strong and permanent joint.