Seamaster Aqua Terra 150M Co-Axial 30 White Gold / Diamond / MOP / Bracelet

In Context

At 30 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. 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. 50 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.

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

8521 sans date. Self-winding movement with Co-Axial Escapement for greater precision, stability and durability. Free sprung-balance system with silicon balance-spring. Automatic winding in both directions to reduce winding time. Oscillating mass and balance bridge in 18 Ct red gold. Luxury finish with exclusive Geneva waves in arabesque.

13 other watches in the library run the Omega 8421.

Omega

LadyMatic Co-Axial 34 Yellow Gold Diamond / Diamond Flower

425.67.34.20.55.005 · 34 mm

Omega

Seamaster Aqua Terra 150M Co-Axial 30 White Gold / Baguette / Baguette / Bracelet

231.55.30.20.99.003 · 30 mm

Omega

LadyMatic Co-Axial 34 Sedna Gold / Diamond / Flower MOP

425.67.34.20.55.009 · 34 mm

Omega

Constellation Co-Axial 31 Red Gold / Snow / Diamond Supernova

123.55.31.20.55.010 · 31 mm