If you landed here because a listing calls itself a replica of the Omega De Ville Trésor 424.10.40.20.02.001, here is the short answer. That reference number belongs to a real Omega: a slim 40 mm steel De Ville on a leather strap, hand wound, with a sapphire display back. Copies of it exist, and the better ones photograph well. They do not feel the same on the wrist, and they fail in ways that matter once the movement stops.
What the genuine watch actually is
De Ville is Omega's dress family, and Trésor is the thin end of it. The name goes back to a 1949 Omega model, revived in the 2010s as a modern slim dress watch with a domed dial and a hand-wound co-axial movement under a clear caseback. The steel version sits in the same size range as the gold ones, which makes it a popular target for counterfeiters, since a tall case is harder to hide in stainless steel than in a chunkier sports watch.
- Round 40 mm steel case, fixed steel bezel, thin profile for its diameter
- Hand-wound Omega co-axial movement, visible through a sapphire caseback
- Silver-toned dial with applied indices, restrained printing, a domed profile
- Leather or alligator strap with a signed pin buckle
- Dress-watch water resistance: fine for rain and washing hands, not for swimming
Omega's own product page for the reference is the only place I trust for the exact calibre number, power reserve, and thickness. Secondary listings repeat each other and drift.
Why a thin hand-wound dress watch is hard to copy
The first tell is height. A copy often runs a little thicker than the original, and on a Trésor the whole point is that a 40 mm watch slides under a cuff. You notice that difference before you notice anything about the dial.
The second tell is the crown. Wind a genuine hand-wound Omega and the drag builds evenly, with a clean click from the first turn. Cheap movements feel gritty, or the crown spins part of a turn before it catches. This is not something a photo can fake and it is the fastest check available to you.
The third is the caseback. Geneva stripes, blued screws, and properly finished bridges take machining time. Many replicas use a plain movement, a printed decorative plate, or a sapphire back that hides as much as it shows. Dial printing is the last giveaway: the Trésor dial is spare, and a spare dial leaves nowhere to hide a heavy font or a marker that sits half a millimeter off center.
What I check first on a 424.10.40.20.02.001
- Measure the case with calipers, both diameter and thickness, rather than eyeballing it
- Wind the crown and count how long before it engages
- Look at the movement through the back under a loupe, not under a phone light
- Compare the dial text weight and the spacing of the markers to photos from Omega
- Inspect the engraving on the caseback, which on copies is often shallow or uneven
- Ask a watchmaker to open it and read the serial, then request an extract from the Omega archives
The part most buyers skip: law and servicing
Counterfeit watches are illegal to import into the United States. CBP seizes them at the border, and the buyer has no recourse and no refund. Beyond that, no Omega service center will touch a fake, and an independent watchmaker will struggle to source parts for a co-axial escapement that was never machined to spec. Resale value is effectively zero. A replica of a steel dress watch also often costs enough that a pre-owned genuine model, or a similarly thin dress watch from another brand, sits within reach.
Bottom line
The reference number is real. The copy is not. If what you want is the look of a thin steel dress watch, there are honest options with their own name on the dial, and they will still be running in five years without a parts hunt.