13”’ | Hammer Automatic | Swiss Lever | Direct Sweeping Seconds |

Remarks:

• Hammer automatic with unidirectional winding, manual winding possible
• Variants of the movement:
  • Zenith 133: 18,000 A/h
    First automatic movement of Zenith
    1948 – 1961, 25,000 pieces
  • Zenith 133.8: 21,600 A/h
• Large spring on the bridge side serves to support the movement against the case back

• Listing ID: 2123
• Manufacturer / Brand: Zenith
• Caliber: 133.8
• Size in French Lignes: 13''' (30.00 mm), Height 4.90 mm
• Size range mm largest diameter: 22 - 31 mm
• Shape: Round
• Winding: Automatic
• Hands Setting: Crown
• Seconds Hand: Sweeping seconds (central seconds)
• Escapement: Lever (Swiss, English, Glashütte)
• Date, Day, Month...: None
• Jewels: 20
• Setting Lever Screw/Pin Position: Right
• Balance Position: Bottom (120 - 240°)
• Shock Protection: Incabloc
• Beats per hour: 21,600
• Balance Type: Monometallic screw balance
• Power Reserve: Approx. 35 hours
• Production Period: 1951 - 1958 (77.000 pieces)
• Country: Switzerland
• Identification: Marked 133.8 under the balance. Original data sheet available.
• Contributor ©: Uhrforum.de member Badener (Andreas Kelz)
• External Link: https://uhrforum.de/threads/identifizierte-uhrwerke-die-weder-bei-ranfft-lorenz-noch-im-watch-wiki-zu-finden-sind.86322/page-42#post-5452295
• External Link 2: https://watch-movements.eu/blog/en/2020/10/03/zenith-movements-in-display-watch-cases/