The Omega caliber 1109 is an automatic movement found in some Omega Seamaster Pro 300M watches from the early 1990s (1993?). This movement can be found in both the full-size 41mm and the mid-size 36mm SMP.
The 1109 is essentially based on the ETA caliber 2892-A2 framework. It has a beat rate of 28,800 4Hz, 21 jewels and a power reserve of 44 hours. This movement has a quickset date, hacking seconds, and can be hand-wound.
This movement was later replaced by the Omega caliber 1120 in the mid to late 90s (1996?).
Note: This caliber listing is still being updated, but feel free to start discussions on it in the comments below…