Railmaster Omega Co-Axial Master Chronometer 38 Stainless Steel / Grey Gradient

In Context

At 38 mm it sits just under the modern norm — the band that suits the widest spread of wrists. At 12.36 mm it is a tall case, and it will catch on a cuff. The case back is closed, so the movement stays out of sight, and the sapphire crystal will resist everything short of deliberate abuse. 150 m is genuine swimming resistance — more than the shape of this watch suggests it would need.

The movement winds itself from the motion of your wrist. 55 hours of reserve is enough to set it down on Friday evening and find it still running on Monday. At 25,200 vph the seconds hand advances 7 times a second.

235.12.38.20.06.001 stands on its own in this catalogue — no other reference here shares its base number. It pairs a grey gradient dial with a stainless steel case. Introduced in 1957.

The 8806 is the 8800 without a date: the same Master Chronometer movement with the calendar works left out. It powers 39 watches in this library, most of them the no-date Seamaster Diver 300M. The [8800](/calibers/omega-8800) is Omega's single-barrel co-axial caliber for mid-size cases, certified by METAS to resist 15,000 gauss, with a silicon balance spring, a free-sprung balance, 35 jewels, a 55-hour reserve and a beat of 25,200 vph. Removing the date removes the window and the crown's second position, and gives a dive watch the symmetrical dial of the 1957 originals. The finish is rhodium with arabesque Geneva waves. In the library it sits under 25 [Seamaster Diver 300M](/brands/omega/seamaster-diver-300m) references, the no-date model of 2018 onward including the titanium No Time To Die edition of 2020, 10 [Railmasters](/brands/omega/railmaster) of 2017, whose anti-magnetic brief the movement's certification answers directly, and 2 each in the Museum Collection and the [Seamaster 300](/brands/omega/seamaster-300). The 42 mm case accounts for 19 references. The [8807](/calibers/omega-8807) is the gold-rotor version of the same base, and the [2403](/calibers/omega-2403) the no-date co-axial of the previous generation.

38 other watches in the library run the Omega 8806.

Omega

Seamaster Diver 300M Master Co-Axial 43.5 Milano Cortina 2026 Winter Olympics

522.92.44.20.04.001 · 43.5 mm

Omega

Seamaster Diver 300M Master Co-Axial 43.5 Sedna Black

210.62.44.20.01.001 · 43.5 mm

Omega

Seamaster Diver 300M Master Co-Axial 42 Titanium - Bronze Gold / Green / Bracelet

210.90.42.20.10.001 · 42 mm

Omega

Seamaster Diver 300M Master Co-Axial 42 Swiss Armed Forces

210.30.42.20.01.003 · 42 mm