Internal Coupling. A streamlined flush joint in two tubes of the same size. Wall thickness must be 3.2 mm. Do not apply direct loads to this joint.
Another big plus of the black coating is, that the color gets into the material really deeply, which prevents the connectors from corroding. The paintwork is not resistant to UV radiation and is therefore not suitable for outdoor use. The tube fittings are equipped with black-colored stainless steel adjusting screws with cutting edge.