11 1/2”’ | Hand Wind | Swiss Lever | Direct Sweeping Seconds | Date |

Remarks:

• Hacking seconds
• Date with quick-setting
• Movement family:
  • MST 520: hand winding, no date
  • MST 521: hand winding, date
  • MST 522: automatic, date
  • MST 523: automatic, date, day
• Last movement family developed by MST

• Listing ID: 13496
• Manufacturer / Brand: MST
• Caliber: 521
• Size in French Lignes: 11 1/2'''
• Size range mm largest diameter: 22 - 31 mm
• Shape: Round
• Winding: Manual (Crown)
• Hands Setting: Crown
• Seconds Hand: Sweeping seconds (central seconds)
• Escapement: Lever (Swiss, English, Glashütte)
• Date, Day, Month...: Date
• Jewels: 17
• Setting Lever Screw/Pin Position: Left
• Balance Position: Bottom (120 - 240°)
• Shock Protection: Incabloc
• Beats per hour: 21,600
• Balance Type: Nickel
• Power Reserve: Approx. 56 hours
• Production Period: 1973 - 1976
• Country: Switzerland
• Identification: Movement marked with MST 521 on a gold-colored plate next to the balance (see extra picture). Original data sheet from 1973 available.
• Contributor ©: Uhrforum.de member buchenhain
• External Link: https://uhrforum.de/threads/identifizierte-uhrwerke-die-weder-bei-ranfft-lorenz-noch-im-watch-wiki-zu-finden-sind.86322/page-72#post-10076036