Quick Answer
The reference block 220.12.41.21 identifies the Omega Seamaster Aqua Terra 150M in a 41 mm stainless steel case. The full number 220.12.41.21.03.001 is the blue teak dial version on a steel bracelet. A replica of this reference is any watch built to imitate that design without Omega's involvement. Replicas of this model fall into three rough tiers: budget builds using quartz or plain automatic movements, mid-tier builds with decorated movements and closer dial work, and top-tier builds that copy the case profile and dial texture closely while still running a third-party movement. None of them are Omega watches, and none carry Omega's warranty, service network, or Master Chronometer certification.
How to Read the Reference Number
Omega reference numbers work in blocks. The first group identifies the collection and case material, the middle groups cover size and movement family, and the final digits cover dial and bracelet variant. That is why 220.12.41.21 can point to several finished watches once the trailing digits change. When a seller quotes only the short block, ask for the complete reference and a photo of the caseback, since the last digits decide dial color and bracelet type.
The Genuine Watch at a Glance
- 41 mm stainless steel case with a symmetric profile
- Blue dial with horizontal teak lines and a date window at 6 o'clock
- Caliber 8900, a Master Chronometer automatic with roughly 60 hours of reserve
- 150 m water resistance rating
- Sapphire crystal front and back, with the movement visible through the caseback
- Steel bracelet with a butterfly clasp
What Replica Builders Tend to Get Right
Case diameter, overall silhouette, and the general look of the teak dial are the easiest parts to copy, and most mid-tier and top-tier builds handle them well enough at arm's length. The bezel-free case shape helps here, because there is no rotating bezel or complex geometry to mismatch. Many replicas also replicate the arrow-tipped hour hand and the applied logo position with reasonable accuracy.
Where Replicas Fall Short
The gaps show up in finish and function rather than shape.
- Dial texture: genuine teak lines are cut with even depth and catch light across the whole dial. Replica lines often look flat or shallow in photos taken at an angle.
- Bracelet and clasp: end link fit, screw tolerances, and clasp action are the usual weak points. A rattling bracelet is a common tell.
- Movement: even decorated replicas use third-party movements. Winding feel, rotor noise, and beat rate rarely match a Master Chronometer caliber.
- Date wheel: font weight and alignment in the 6 o'clock window are frequently off by a fraction of a millimeter.
- Crystal: anti-reflective coating on replicas is often thinner, so the dial washes out under bright light.
How to Vet a Replica Seller Before You Pay
- Ask for dated photos of the exact unit you will receive, including the caseback, clasp, and lume shot.
- Request a short video showing the second hand sweep and the date change at midnight.
- Confirm the movement name in writing and check that it matches what the listing claims.
- Verify the return window and who pays return shipping if the watch arrives damaged.
- Pay with a method that allows a chargeback, never by wire or gift card.
- Save the full listing, chat log, and payment receipt in one folder.
Legal and Practical Reality
Counterfeit watches infringe registered trademarks, and customs agencies in the United States and the European Union seize them on sight. Buying one is a private transaction in most places, but importing or reselling them carries real legal exposure. Practical downsides matter too: no manufacturer service, no parts support, no water resistance guarantee, and almost no resale value. If a functioning 150 m dive-style watch with a reliable movement is the goal, a mid-range Swiss or Japanese watch costs less than a top-tier replica and can be serviced anywhere.