It's really a type of threaded insert. There's two types: one particular is designed to kind a bulge over the back aspect with the panel as a screw is tightened in its threads. Another is equally drawn in utilizing a screw, but is drawn into your sleeve as an alternative https://andersonqiwlx.ivasdesign.com/48831602/the-fact-about-threaded-inserts-for-plastics-that-no-one-is-suggesting