Hi all, received a new old stock set of Enkei/AMEs in the post today and these 4 things were in one of the boxes. I literally have no idea what they are, probably due to the fact every car I've ever owned has had the factory steelies or the standard alloys, I've never had any sort of aftermarket wheels on any car at all. They split into two parts and have a thread. Think it has something to do with the centre caps but not entirely sure.
Both serious and not so serious replies/help encouraged, thanks ?