Ed.
is it a "blind" thread. That is, a threaded inside, and something that "grips" to the surface. It is hard to tell from your image. If it is what I think it is, then I have a source here (in NZ).
Gary
Yes Gary it is threaded inside, the idea is when the tube connector is (slipped under a slight pressure) inside a round tube and a bolt wound into it and tightened it grips to the inside wall securing the end of the pipe.
Tube connectors
