There is only you and your camera. The limitations in your photography are in yourself, for what we see is what we are.
A paper binder clip?
Great shot - love the detail and lines! And, I'll 'third' the guess of a binder clip! ;)
You are all correct! I will have to come up with something more difficult the next time I do something like this! Haha.
I was going to say some sort of file clip :-)
I actually knew what this was before looking at the comments. As a teacher I use these quite often. Great close up.