Is it a pile of metal rings for use on the end of a rope - y'know, the ones used on the end of the ropes holding a ship to the quay?
I'm beaten. I can only think of open rings that can be attached to something else, such as to a gate or to make a door knocker or drawer handle. They seem to me, to be about 10 inches diameter so it must be a bleedin' big door/drawer if it's not for gates. lol