These inserts are designed to be glued into the Penthalon Traditional shafts. They are made of aluminium and are tapped to take the 3D 5/16th Combi Points. My chosen glue for the job is Araldite Ultra or any quality epoxy resin. Many people use hot melt glues or super glue. From experience I have found hot melt unreliable with inserts being let in hard 3D targets. Super glues work but can go brittle over time. It's also not possible to remove them if you had a cause to do so. Epoxy, like hot melt goes soft when warmed up and they can be removed if needed.
Inserts and screw in points are an alternative to speed points for the Penthalon traditional range of shafts. One advantage with the speed points though is that they are made of stainless steel and much harder and resitent to the element than 3D screw in points.