MY5
IAN,
To me this looks like a seal. It starts with a wire. One end is flattened and a hole punched through. The other end, while
still plain is fed through a bag or box or lock or whatever is being sealed, then fed through the hole in the flattened end. Then the plain end that was just fed through the hole is struck with a hammer, or more likely a punch with letters
engraved on the bottom, which flattens it out slightly. I would however expect it to be cut but maybe the item it was attached to was cut instead.
You can see modern versions used in the shipping and trucking industry these days.
I have never seen anything like this and it strikes me as an early-modern item, say 18th-early 20th century, but this is really just a guess. I might be completely wrong. I have just never heard of anything like this in the ancient world and this is clearly a well-though out, advanced item.
Shawn