13 1/2”’ | Automatic | Swiss Lever | Small Seconds at 9 H | Date at 3 H | 24 H Indication from Center |

Remarks:

• Automatic with unidirectional winding
• Small seconds with hacking
• Date at 3 H with quick adjustment via middle crown position
• Perlage decoration
• Ball-bearing rotor
• According to Watch-Wiki, the ST25 has 23,400 bph. However, all the ST25 versions I have seen so far have always had 21,600 bph
• Part of a very large ST25/TY25 movement family:
  • ST2501:
    Automatic, hour/minute in the center, small seconds at 9 H, visible balance at 6 H
  • ST2502:
    Automatic, hour/minute/seconds in the center, date hand at 3 H, day of the week indicator at 9 H, visible balance wheel at 6 H
  • ST2503:
    Automatic, hour/minute/seconds in the center, date hand at 3 H, day of the week indicator at 9 H, month + year at 12 H, visible balance wheel at 6 H
  • ST2504:
    Automatic, hour/minute/seconds in the center, retrograde date display at 9 1/2 H, retrograde day of the week display at 2 1/2 H, visible balance wheel at 6 H
  • ST2505:
    Automatic, hour/minute/seconds in the center, retrograde date display at 9 1/2 H, power reserve indicator at 2 1/2 H, visible balance at 6 H
  • ST2508:
    Automatic, minute in the center, hour at 12 H, small seconds at 6 H
  • ST2509:
    Automatic, hour/minute/seconds in the center, power reserve indicator at 12 H, visible balance at 6 H
  • ST2510:
    Automatic, hour/minute/seconds in the center, second time zone at 12 H, visible balance wheel at 6 H
  • ST2525:
    Automatic, hour/minute/seconds in the center, day of the week indicator at 3 H, month indicator at 9 H, large date at 12 H, visible balance wheel at 6 H
  • ST2526:
    Automatic, hour/minute in the center, small seconds at 6 H, big date at 12 H
  • ST2527:
    Automatic, hour/minute/seconds in the center, day of the week indicator at 8 H, month indicator at 4 H, big date at 12 H
  • ST2528:
    Automatic, hour/minute in the center, small seconds and moon phase at 6 H, big date at 12 H
  • ST2529:
    Automatic, hour/minute/seconds in the center, 24-hour display at 6 H, weekday indicator at 3 H, month display at 9 H, big date at 12 H
  • ST2530:
    Automatic, hour/minute in the center, small seconds at 9 H, date at 3 H, power reserve indicator at 5 H
  • ST2531:
    Automatic, hour/minute/seconds in the center, date at 1 1/2 H, power reserve indicator at 6 H, crown at 4 H
  • ST2532:
    Automatic, hour/minute in the center, small seconds at 9 H, date at 6 H, power reserve indicator at 3 H
  • ST2533:
    Automatic, hour/minute/24 h indicator in the center, small seconds at 9 H, date at 3 H, power reserve indicator at 6 H
  • ST2540:
    Automatic, hour/minute/seconds in the center, year/month/24 h/day of the week arranged in a row from 8 to 4 H, big date at 12 H
  • ST2542:
    Automatic, hour/minute in the center, small seconds at 6 H, power reserve indicator at 12 H
  • ST2545:
    Automatic, small seconds in the center, hour/minute at 3 H, second time zone at 9 H, retrograde date at 6 H, power reserve indicator at 12 H
  • ST2551:
    Automatic, hour/minute/seconds in the center, date at 3 H
  • ST2551-S:
    Manual winding, hour/minute/seconds in the center, date at 3 H
  • ST2552:
    Automatic, hour/minute/seconds in the center, 24-hour indicator at 6 H, date at 4 1/2 H, day of the week indicator at 9 H, month indicator at 3 H
  • ST2553:
    As ST2551, but diameter 37.2 instead of 30.4 mm
  • ST2555:
    Automatic, hour/minute in the center, small seconds at 9 H, date at 3 H
  • ST2557:
    Automatic, hour/minute and 24-hour indicator in the center, small seconds at 9 H, date at 3 H
  • ST2561:
    Automatic, hour/minute in the center, date at 3 H, power reserve indicator at 6 H
  • ST2563:
    Automatic, small seconds in the center, hour/minute at 3 H, second time zone at 9 H, large date at 6 H, power reserve indicator at 12 H
  • ST2571:
    Automatic, hour/minute/seconds in the center, day/night indicator and small hand date at 12 H, visible balance wheel at 6 H
  • ST2590:
    Automatic, hour/minute/seconds in the center, perpetual calendar (day of the week at 9 H, month at 6 H, day at 3 H, 4-year display at 4 1/2 H, moon phase at 12 H)

• Listing ID: 2176
• Manufacturer / Brand: Sea-Gull / Seagull
• Caliber: ST2557 / TY2557
• Size in French Lignes: 13 1/2''' (30.4 mm), Height 7.4 mm
• Size range mm largest diameter: 22 - 31 mm
• Shape: Round
• Winding: Automatic
• Hands Setting: Crown
• Seconds Hand: Small seconds
• Escapement: Lever (Swiss, English, Glashütte)
• Date, Day, Month...: Date
• Other Functions: 24h Indicator
• Jewels: 30
• Setting Lever Screw/Pin Position: Right
• Balance Position: Left (240 - 360°)
• Shock Protection: Similar to Incabloc
• Beats per hour: 21,600
• Balance Type: Glucydur
• Power Reserve: Unknown
• Production Period: Probably starting before 2013
• Identification: Listed in the Sea-Gull catalog 2013
• External Link: https://uhrforum.de/threads/identifizierte-uhrwerke-die-weder-bei-ranfft-lorenz-noch-im-watch-wiki-zu-finden-sind.86322/page-41#post-5319053
• Country: China
• Contributor ©: Uhrforum.de member Badener (Andreas Kelz)