Omega Introduces the Seamaster Planet Ocean GMT “Dark Grey”

Ceramic on the outside, titanium on the inside.

After shading the Aqua Terra Worldtimer line in greys and greens, Omega debuts the Seamaster Planet Ocean GMT “Dark Grey”. A new take on its dive-ready GMT, the watch  is named after the dark grey ceramic case, which harnesses the material’s hardness while staying lightweight thanks to the extensive use of titanium for its internals, including the movement bridges.

Initial thoughts

Titanium and ceramic are not noteworthy in themselves, but here the materials are combined in an interesting and functional manner. The scratch resistance of ceramic is useful for the case, while the titanium inner components keep the weight down, a helpful characteristic for a big watch.

And the materials also create a shades-of-grey appearance that gives the watch a sense of seriousness – with the orange accents bringing some tasteful contrast – though it is less stark compared to its all-black ceramic sibling

Thought lighter than usual for a watch of its size, the new GMT is a big watch measuring 45.5 mm in diameter, making it quite a bit bigger than comparable watches from Tudor for instance.  It would be more wearable and have a wider appealing if the case was in the range of 41 mm to 42 mm.

Despite its material attractions, however, the GMT “Dark Grey” is expensive at US$22,200. It is  almost twice as expensive as the same model in black ceramic (that admittedly doesn’t have a titanium movement). Despite the titanium components, the price is hard to justify since it is by and large the same watch.

Shades of grey

The “Dark Grey” retains the standard design of the Planet Ocean GMT, but is rendered in materials not used before. Its dimensions are identical to the version in black ceramic, with the case measuring a hefty 45.5 mm in diameter and 14.7 high.

However, the case is silicon nitride ceramic, a composite of silicon nitride and ceramic that has superior physical properties compared to regular ceramic. In particularly, it is lighter and stronger, both useful attributes for a watch case.

The case shares the same patented construction found on other Planet Ocean models. The back is secured by a Naiad Lock, a bayonet-locking mechanism that ensures it is perfectly aligned with the case.

The insides of the watch are mostly titanium. The dial is sandblasted titanium with applied anthracite hour markers and hands. Additionally, the same alloy is used for the helium escape valve, bezel, and inner chapter ring.

Most notable is the cal. 8906 Ti, a variant of the standard cal. 8906. The cal. 8906 Ti retains all of the functions of the standard version, namely the user-friendly dual time zone function set via the crown. But it features a main plate and bridges in sandblasted titanium, which affords significant weight reduction over the brass components of the standard calibre.

Like most Omega movements, the cal. 8906 Ti is accompanied by METAS certification, which attests to its exceptionally high magnetism resistance of over 15,000 Gauss, owing to the silicon hairspring and paramagnetic alloys for the escapement.

Key facts and price

Omega Seamaster Planet Ocean 600M Co-Axial Master Chronometer GMT 45.5 mm “Dark Grey”

Diameter: 45.5 mm
Height: 17.4 mm
Material: Grey ceramic
Crystal: Sapphire
Water resistance: 600 m

Movement: Cal. 8906 Ti
Functions: Hours, minutes, seconds, date and second time zone
Winding: Automatic
Frequency: 25,200 beats per hour (3.5 Hz)
Power reserve: 60 hours

Strap: Rubber strap with folding clasp

Limited edition: No
Availability: At Omega boutiques and retailers
Price: US$22,200

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