Omega Caliber 1120 Complete Guide
The Omega caliber 1120 is a movement from Omega that is, like so many other movements from Omega’s history, based on an ETA movement. More specifically, the ETA 2892-A2.
Omega has then modified the caliber to give it better performance and to make it more visually pleasing. The original ETA movement has 21 jewels, but Omega’s modified version has 23. Furthermore, the ETA movement is not a certified chronometer (COSC), but the modified version is. Omega also uses a 3-arm Glucydur balance in the modified movement.
The ETA movement used is a tried and true caliber that has proven itself to be a sturdy and reliable workhorse. Just the characteristics you’d want in a movement. In particular, a movement that is to be used in the sporty Seamaster.
The Caliber 1120 is the predecessor to the Omega caliber 2500. The revolutionary part about the 2500 was that it featured the co-axial escapement, whereas the 1120 does not. The 1120 is a self-winding mechanical movement equipped with a ball-bearing rotor. In terms of functions, it has hacking seconds, date function, and displays hours and minutes. It offers a power reserve of 44 hours.
Modified versions of the Caliber 1120
Omega has several modified versions of the caliber 1120. These have been modified to have different functions and purposes.
- Omega Caliber 1128
The Caliber 1128 is the 1120 movement with an additional (GMT) hour hand.
- Omega caliber 2400
The Caliber 2400 is the 1120 movement which has been skeletonized and had the date function removed
- Omega Caliber 2401
The Caliber 2401 is the 1120 movement skeletonized and had the date function removed. It is made of yellow gold.
Omega Caliber 1120 Specifications
- Frequency: 28800 BPH
- Jewels: 23
- Power reserve: 44 hours
- Functions: Seconds, minutes, hours, hacking seconds, rapid calendar advance, Date function.
- Technology: Self-winding, COSC certified, Yoke winding system, Shock protection, Nivarox-1 balance spring with Etachron adjustment device.
- Diameter: 25.60mm
- Thickness: 3.60mm
Main photo by daboosh via Watchuseek.
I have just acquired an Omega Seamaster 300 Professional, caliber 1109, case 34mm without helium crown. To my surprise I found on the back NOT FOR SALE and L90 or 067. Interior caseback inscription 096. ST 0041. Movement references;
49(x)672840 and 289242. Could this be a prototype, example a Jacques Mayol 2553.41.00 ? The 1120 is “reserved for a 1109” (Omega Saga). Greetings.
Hi,
Watches that have “not for sale” are often display watches used by the company. This can be, for example, when Omega shows its new watches at a fair after a release. With that said, it’s a very interesting engraving to have which could say something about the watch’s provenance.
Kind regards,
Millenary Watches
096ST0041 is the part reference of the antimagnetic cover.
49672840 is the serial number of the movement – and this is an early/mid 1990’s production.
289242 is actually 2892-2. Very early caliber 1109 actually had the ETA caliber on the mainplate as well.
Your watch should be a Reference 168.1501 as that is the Seamaster w/o Helium valve.
168.1502 would be a mid-size 300 Pro and 168.1503 would be the fill-sixe 300 Pro.