Pocketwatch to wristwatch conversions
As the twentieth century got under way and wristwatches became more prominent, owners of ladies pocket watches, like the Hampden size 3/0 models, were offered conversion kits by enterprising companies (The advert below is for the Keystone Co.). These kits had many benefits like; the practical conversion to a wristwatch, re-cycling a family heirloom; the chance to sell the original gold, or silver, case for cash; when combined with the re-dial option it made them suitable for a man.
These were not factory options and were made for other manufacturers as well as Hampden. The criteria is that the winding stem is at the 3 O'clock position.
The watches pictured below simply demonstrate the stages. One conversions has an original dial the other (far right) had a replacement.