It is a vintage bracelet made by Campagnolo. As both a vintage watch and race bicycle guy that is sort of perfect. I have not been able to prove that the bracelet actually was made by "that" Campagnolo but it does not matter much as it such a beauty.
My heart stopped for a sec there. I used to cycle as a teen and my Peugeot was fitted with Campagnolo gear such as this....them were the days! What frame is the running gear fitted on?