OMEGA · Seamaster Aqua Terra 150M
OMEGA Aqua Terra 220.10.41.21.01.002: specifications and what to check
The everyday Seamaster: 150 metres, sapphire both sides, and a calibre with twin barrels and an independently adjustable hour hand. The time zone function is the feature most listings forget to mention.
Reference 220.10.41.21.01.002 · specifications read from the manufacturer on 2026-09-23 · listed as current
Specifications
As published by OMEGA. A field the manufacturer does not state is left out rather than filled in.
- Case
- Steel, 41 mm
- Diameter
- 41 mm
- Thickness
- 13.4 mm
- Lug width
- 20 mm
- Lug to lug
- 48 mm
- Water resistance
- 15 bar (150 metres / 500 feet)
- Crystal
- Domed scratch-resistant sapphire crystal with anti-reflective treatment on both sides
- Dial
- Black
- Bracelet
- Steel
- Clasp
- Foldover butterfly clasp with comfort setting
Movement
- Calibre
- Calibre OMEGA 8900
- Type
- Self-winding movement with Co-Axial escapement, automatic winding in both directions
- Power reserve
- 60 hours
- Certification
- Master Chronometer, approved by METAS
- Notes
- Resistant to magnetic fields reaching 15,000 gauss. Free sprung-balance with silicon balance spring, two barrels mounted in series, and a time zone function. Rhodium-plated rotor and bridges with Geneva waves. Total product weight approximately 148 g.
What to check before you buy
- Test the time zone function properly: the hour hand should jump independently in one-hour steps without disturbing the minutes or seconds. A hand that drags the minute hand with it is a fault, not a quirk.
- Check the anti-reflective coating on both crystal surfaces. OMEGA specifies treatment on both sides, and worn or patchy coating on the inner face cannot be polished away — it needs a new crystal.
- Wind and run it for a full day to confirm the 60-hour reserve behaves. Twin barrels in series should deliver consistent amplitude rather than fading early.
- Verify the calibre is the 8900 rather than an 8800 or a 2500-series from an earlier Aqua Terra. The case looks similar across generations and the movement does not.
- Note the rating is 150 metres with a screw-down crown — genuinely swimmable, unlike the Speedmaster, and worth saying so to a buyer choosing between them.
The feature nobody mentions
OMEGA lists a time zone function on the 8900, and it is routinely left out of listings entirely. It means the hour hand can be moved forward or back in one-hour steps on its own, without stopping the watch or disturbing the minute hand.
For anyone who travels, that is the difference between a watch that adjusts in two seconds on landing and one that has to be reset from scratch. It is a genuine selling point sitting unused in most descriptions of this reference.
It is also an inspection point. Step the hour hand through a full circuit both ways. If the minute hand creeps along with it, or the hour hand does not land cleanly on the markers, that is a fault worth finding before you own it.
Two barrels, and why it shows
The 8900 carries two barrels mounted in series and winds in both directions, which is how OMEGA gets 60 hours out of it without running the mainspring hard at the end.
The practical test is simple and worth doing on any used example: wind it fully, wear it, and see whether it is still keeping time at the far end of the reserve rather than losing amplitude overnight. A watch that fades early is telling you something a five-minute check on the counter will not.
Sapphire on both sides means what it says
The crystal is domed sapphire with anti-reflective treatment on both faces. The outer coating wears with use, which is normal. The inner one should not — and if it looks patchy or hazed from the inside, that is not something a polish will reach. The crystal has to be replaced.
Look at the dial through the crystal at an angle, with a light behind you. Interior coating problems show as uneven bloom rather than as scratches.
Where it sits against the Speedmaster
Worth being clear with a buyer choosing between OMEGA's two obvious steel sports watches. This one is 150 metres, self-winding, sapphire, with a screw-down crown — an everyday watch you can swim in.
The Moonwatch is 50 metres, hand-wound, and specified with a plastic crystal in its most traded form. Both are excellent; they are not alternatives to one another, and selling one to someone who wanted the other ends in a return.
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Sources
Not affiliated with OMEGA. Specifications are read from the manufacturer's own published documentation on the date shown and may change; the manufacturer's current documentation governs.