Omega Seamaster Diver 300M 210.30.44.51.06.001

The movement is the N1 Custom Cal. 9900, built on a heavily modified Asian 7750 automatic chronograph base. A custom module is used to recreate the reference’s unusual 3 o’clock co-axial chronograph display, physically linking the 12-hour and 60-minute hands within that subdial for true elapsed time tracking. Running seconds are placed at 9 o’clock, completing the core chronograph layout, while the date remains at 6.

This movement runs at 28,800 vibrations per hour and offers approximately 40 hours of power reserve. Through the caseback, the movement is decorated to reflect the look of the genuine Calibre 9900, including blackened screws and Arabesque Geneva waves. For buyers focused on this specific Seamaster chronograph reference, the movement architecture is central to the appeal, because the 3 o’clock subdial is not merely decorative.