Bucks,
It was first released in the year 2000.
Here are some more details about the movement. This information was found at this website:
https://watch-wiki.org/:
Automatic movement with double bridge, suitable for "open heart" applications (from the dial visible balance, in the style of Vacheron Constantin ). 25 jewels, 21,600 vibrations, 48 hours power reserve, ball-bearing rotor. In-house development by Tianjin Seagull from the year 2000. The work is available with various complications, including a perpetual calendar , and today represents the main line of the Seagull caliber.
Variants:
2501 - Small second at 9, visible balance at 6, 25 stones
2502 - center seconds, date hand at 3, weekday hand at 9, visible balance at 6, 29 jewels
2503 - sweep second, date hand at 3, weekday hand at 9, year and month at 12, visible balance at 6, 29 jewels
2504 - sweep second , retrograde date at 9:30, retrograde weekday at 2:30, visible balance at 6, 33 jewels
2505 - sweep second , retrograde date at 9:30, power reserve indicator at 2:30, visible balance at 6, 38 jewels
2508 - central minute, hour at 12, small second at 6
2510 - center seconds, independent 2nd time zone at 12, visible balance at 6
2525 - center seconds, two-digit date at 12, month hand at 9, weekday hand at 3, visible balance at 6
2526 - Small second at 6, two-digit at 12
2527 - sweep second, two-digit date at 12, month hand at 4, weekday hand at 8
2528 - Small second and moon phase at 6, two-digit date at 12
2530 - Small second at 9, date at 3, power reserve indicator at 5
2531 - sweep second, date at 1:30, power reserve indicator at 6, crown at 4
2540 - sweep second, year, month, 24h and day of the week from 8 to 4, two digits at 12
2542 - Small second at 6, power reserve indicator at 12
2545 - sweep second, 1st time zone (hour, minute) at 9, 2nd time zone (hour, minute) at 3, retrograde date at 6, power reserve indicator at 12, 45 jewels
2551 - center seconds, date at 3 (also available as manual wind version, ST2551-S)
2590 - sweep second, day of the week at 9, month at 6, day at 3, 4-year display at 4.5, moon phase at 12, perpetual calendar, 39 stones [1]