Long before the introduction of struck coinage into ancient Celtic Europe, these copper rings were used as currency by Celtic tribes and were often worn on clothing or tied together by ropes. These particular rings, often refered to as "proto-money", were created in ancient Moesia (Bulgaria) as long ago as 7th Cent. B.C. The sizes range from 10mm-40mm.
Yes, I know they really don't belong in this particular catagory, but they seem to fit in with the "funny money" scheme of things, eh? ;-)
If you'd like to wear one as a ring (how many of you can brag that your ring is 2,700 years old?), tell me your ring size and we'll do the rest. Cool, huh?