" At The outset, these wristwatches had been a single-off or custom creations That usually looked a lot similar to the pocket watches from which they progressed. But shortly, wristwatches took on their own aesthetic, with their particular technological innovations to unravel new challenges offered by wrist-borne timekeepers. Indeed, Piaget https://www.watchesworld.com/a-history-of-watch-reference-numbers/