It is just a kind of threaded insert. There are 2 styles: a single is built to form a bulge within the back again aspect of the panel being a screw is tightened in its threads. One other is in the same way drawn in using a screw, but is https://zionibskz.thezenweb.com/the-best-side-of-threaded-inserts-for-plastics-64219992