De Ville Co-Axial 32.5 Yellow Gold Diamond / MOP / Bracelet

In Context

At 31.1 mm it is small by current standards, in the range most wristwatches occupied before cases began growing through the 1990s. The case back is open, so the movement is visible without taking the watch apart, and the sapphire crystal will resist everything short of deliberate abuse. 100 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. 48 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.

4186.75.00 stands on its own in this catalogue — no other reference here shares its base number. It pairs a white dial with a yellow gold case.

The 2500 is the first co-axial caliber: an ETA 2892-A2 rebuilt around George Daniels's escapement, launched in 1999. It powers 398 watches in this library, more than any other Omega mechanical movement. The co-axial escapement replaces the sliding friction of the Swiss lever with pushing impulses on two wheels, so it needs less lubrication and holds its rate longer between services. Omega put it on the 2892 base, whose thinness the [2892 piece](/blog/the-eta-2892) explains, and refined it through four generations: the 2500A and B of 1999 to 2006, the 2500C of 2006 that dropped the beat to 25,200 vph to suit the escapement, and the 2500D of 2011 with a three-level escapement wheel. The movement has 27 jewels, a 48-hour reserve and a 25.6 mm diameter, and every one is a COSC chronometer. In the library it sits under 206 [De Villes](/brands/omega/de-ville), 76 [Constellations](/brands/omega/constellation), 51 first-generation [Planet Oceans](/brands/omega/seamaster-planet-ocean), 47 [Aqua Terras](/brands/omega/aqua-terra) and 18 [Seamaster Diver 300Ms](/brands/omega/seamaster-diver-300m). Cases run from 31 mm to 45.5 mm, with 35 mm, 39.5 mm and 32.7 mm the most common, all De Ville Prestige sizes. The [2403](/calibers/omega-2403) is the same movement without the date, the [2627](/calibers/omega-2627) adds small seconds and a power reserve, and the in-house [8500](/calibers/omega-8500) is the movement Omega designed to replace it.

397 other watches in the library run the Omega 2500.

Omega

Seamaster Planet Ocean 600M Co-Axial 42 Stainless Steel / LiquidMetal / Bracelet

222.30.42.20.01.001 · 42 mm

Omega

Seamaster Aqua Terra 150M Co-Axial 36.2 Stainless Steel / Silver

2804.30.37 · 36.2 mm

Omega

Seamaster Planet Ocean 600M Co-Axial 45.5 Mécanique 16 Sapphires

2905.50.38 · 45.5 mm

Omega

Seamaster Planet Ocean 600M Co-Axial 42 Red Gold / Black / Alligator

222.63.42.20.01.001 · 42 mm