Seamaster Diver 300M Automatic 36.25 Yellow Gold / White / Bracelet

In Context

At 36.25 mm it is classically proportioned: the size a dress watch was understood to be for most of the twentieth century, and small enough to sit under 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. 300 m is a professional diving rating, far past any demand a wrist is likely to make of it.

The movement winds itself from the motion of your wrist. 44 hours of reserve carries it overnight, but not through a weekend in a drawer. At 28,800 vph the seconds hand advances 8 times a second.

2151.20.00 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 1109 is Omega's ETA 2892-A2 of the early 1990s, the non-chronometer automatic of the mid-size Seamaster. It powers 19 watches in this library. The 2892 is the thin automatic the [2892 piece](/blog/the-eta-2892) describes, and the 1109 is that base with Omega's finishing, 21 jewels, a 44-hour reserve and a beat of 28,800 vph at 25.6 mm across. The [1120](/calibers/omega-1120) that followed is the same movement adjusted and certified as a chronometer, with two more jewels, and the two ran side by side in the Seamaster of the 1990s. In the library it powers 11 [Seamaster 120M](/brands/omega/seamaster-120m) references at 36.25 mm, most of them in yellow gold, and 8 [Seamaster Diver 300M](/brands/omega/seamaster-diver-300m) mid-size references. The [2500](/calibers/omega-2500) is the co-axial movement Omega later built on the same base.

18 other watches in the library run the Omega 1109.

Omega

Seamaster Diver 300M Automatic 36.25 Stainless Steel / White / Bracelet

2552.20.00 · 36.25 mm

Omega

Seamaster Diver 300M Automatic 36.25 Stainless Steel / Yellow Gold / Blue / Bracelet

2452.80.00 · 36.25 mm

Omega

Seamaster Diver 300M Automatic 41 Stainless Steel / Yellow Gold / White / Bracelet

2432.20.00 · 41 mm

Omega

Seamaster Diver 300M Automatic 36.25 Stainless Steel / Yellow Gold / White / Bracelet

2452.20.00 · 36.25 mm