Read this!
http://queenzone.com/queenzone/forumnew/forum_topic_view.aspx?Q=485816
This has been discussed on QZ before and I gave the same answer then.
It is an upper arm black leather bracelet with silver studs on it. There are many ''artsy'' avante garde shops right here in Baltimore, Maryland USA that carry them. Mostly on a place called Read Street.
I myself, have 2. One for my upper arm, one for my throat which is a type of choker necklace (but idiots often have coined them here in the USA..dog collars).
I stopped wearing mine in the late 1980's, when I got older and they also went out of fashion, but I still have both. When I was younger and booked 2 local bands and went to alot of clubs, I always wore mine.