" At The outset, these wristwatches ended up 1-off or custom creations That usually appeared a good deal such as pocket watches from which they advanced. But shortly, wristwatches took by themselves aesthetic, with their particular technical improvements to solve new issues offered by wrist-borne timekeepers. Exclusions may well use. https://www.watchesworld.com/a-history-of-watch-reference-numbers/