Waltham produced an "0" sized movement called the Ruby. As I recall, quite a high grade for an "0" size. You dad's watch shows up in the "Bible" as a Ruby, and is listed as having a 14-karat white gold case, with vitreous enamel Arabic numerals on the bezel. Circa the late 1920s. I can see evidence on the case lugs of him having worn this watch a lot with metal bracelets on it! Good to see you are now wearing it on a strap! The styling of this one, the Hamilton "Piping Rock", and numerous other similar styles by Waltham, Hamilton, and Elgin are highly sought after today. Nice!
