This is a style of threaded insert. There are 2 styles: 1 is meant to form a bulge about the again facet on the panel to be a screw is tightened in its threads. The other is likewise drawn in utilizing a screw, but is drawn in the sleeve instead https://andersonkaoco.ampedpages.com/considerations-to-know-about-inserts-for-metal-alloy-54045889