The 120T caliber is not especially rare; the total output is estimated at 18,000 movements, produced until 1963. However, finding the Extra R.R. line on the dial is definitely noteworthy, as it indicates a refined version made for the Canadian railways (R.R. standing for railroad), a client that demanded the highest precision possible. The dial configuration itself confirms the purpose of this watch, displaying the familiar red numerals for the afternoon hours, as seen on many other railroad watches made by Cyma, Longines, and Universal Genève. This 35mm wristwatch was undoubtedly made for a specific environment; however, for total peace of mind I would have preferred to see the Extra R.R also mentioned on the 120T caliber, as seen in this example. That said, the 766A966 serial on the caseback falls squarely in the range that Zenith provided for this production of the Extra R.R. wristwatch. Lastly, the embossed emblem on the crown indicates that it’s a replacement, as it corresponds to the logo adopted when Zenith and Movado merged, after 1969.