It is a type of threaded insert. There are 2 forms: a person is designed to form a bulge around the back facet of the panel to be a screw is tightened in its threads. One other is in the same way drawn in employing a screw, but is drawn https://variable-frequency-drive39506.full-design.com/the-greatest-guide-to-threaded-inserts-for-plastics-69346943