What's this?

Yesterday I said I'd do it, today I changed the tyres of D's and my cars indeed. The thing I pictured today might not be known to all. It is a "wheel screw lock socket" (or just wheel lock). It is used instead of a regular bolt, and you need a special key to unlock the wheel.
I don't know how many different of these locks exist, but I don't think rim thieves will have a series of them handy. So my rims are quite safe.