Seamaster Planet Ocean 600M Co-Axial 43.5 Master Chronometer Stainless Steel / Blue / Bracelet

In Context

At 43.5 mm it is a large watch — well above this catalogue’s 40 mm median, and enough to dominate a narrow wrist. At 16.09 mm it is very tall, and sits high off the wrist. 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. 600 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. 60 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.

215.30.44.21.03.001 stands on its own in this catalogue — no other reference here shares its base number. It pairs a blue gloss dial with a stainless steel case. Introduced in 2016.

The 8900 is the first Master Chronometer movement, introduced in the Globemaster in 2015 and certified by METAS to resist 15,000 gauss. It powers 89 watches in this library. It is the two-barrel [8500](/calibers/omega-8500) architecture made anti-magnetic: a silicon balance spring on a free-sprung balance, non-magnetic alloys through the escapement, and the METAS tests that check the cased watch in a 15,000 gauss field, for daily rate between 0 and +5 seconds, and for water resistance. The reserve is 60 hours from two barrels in series, the beat 25,200 vph, the diameter 29 mm with 39 jewels, and the finish rhodium with arabesque Geneva waves. The 8901 is the same movement with a gold rotor and balance bridge. In the library it sits under 40 [Aqua Terras](/brands/omega/aqua-terra), the 41 mm model of 2017 onward, 17 [Constellations](/brands/omega/constellation), the 41 mm Gents of 2020, 17 [Planet Oceans](/brands/omega/seamaster-planet-ocean) at 43.5 mm, 8 [Globemasters](/brands/omega/globemaster) and 7 [De Villes](/brands/omega/de-ville). The 41 mm case accounts for 63 references. The [8800](/calibers/omega-8800) is the single-barrel version for mid-size cases, and the [9900](/calibers/omega-9900) the Master Chronometer chronograph.

88 other watches in the library run the Omega 8900.

Omega

Seamaster Aqua Terra 150M Master Chronometer 41 Stainless Steel / Sedna Gold / Grey / Bracelet

220.20.41.21.06.001 · 41 mm

Omega

Seamaster Aqua Terra 150M Master Chronometer 41 Stainless Steel / Black / Bracelet

220.10.41.21.01.001 · 41 mm

Omega

Seamaster Aqua Terra 150M Master Chronometer 41 Stainless Steel / Blue / NATO / Shaun White Edition

220.12.41.21.03.003 · 41 mm

Omega

Seamaster Aqua Terra 150M Master Chronometer 41 Stainless Steel / Blue / Bracelet

220.10.41.21.03.004 · 41 mm