I think those go on the RD mounting bolt. Not sure????
Ese dicho que me han dicho que tú has dicho que yo he dicho, ese dicho no lo he dicho, porque si lo hubiera dicho, ese dicho estaría bien dicho por haberlo dicho yo.
those little dealies hold the cable adjusting screws in place on a set of campy brakes, until the mechanic (um, you) put the cables in place to hold the screws. Then, you throw 'em in the trash, unless you are the eBay creative sort, and serve 'em up to an unsuspecting public (they are, after all, virgin cardboard).
All that said, I do, in fact, have a set much like this squirreled away.