Short answer: "fake Omega 151" is not an Omega model number. No such reference exists in Omega's catalog. The 151 is a listing code, batch tag, or seller shorthand that gets attached to a replica, and it tells you almost nothing about the watch itself. Judge the piece in front of you instead: movement, case finishing, dial printing, lume, crystal, bracelet, and weight.
Where the 151 tag comes from
Replica production runs in batches. Factories push a few hundred or a few thousand units of one config, then retool for the next one. Sellers need a way to tell those runs apart in a spreadsheet, so they append numbers to the model name. Sometimes the number is a stock keeping unit. Sometimes it is the batch number. Sometimes it refers to weight in grams, or to a case diameter, or to the third revision of the same dial color.
That is why one seller's "151" has nothing to do with another seller's "151." If you search the number across several sites and get three different watches, you have your answer about what it means.
What a real Omega reference looks like
Modern Omega references are long. Something like 210.30.42.20.03.001 breaks down into family, case material, size, movement, dial, and variant. Vintage Omegas from the 1950s and 1960s use short case references, but those are still three or four digits before the decimal and they are documented in collector databases. A bare "151" does not fit either format, which is the quickest way to spot that the code came from a shop and not from Biel.
What actually separates a good replica from a bad one
- Movement. A decorated generic automatic like an A2824 runs fine and keeps decent time. A true clone of the Omega 8500 or 8800 family gets you the correct beat rate, correct power reserve claim, and a rotor that does not look like a sticker.
- Case finishing. Run a fingernail along the lugs. Sharp edges on the brushed surfaces mean the case was stamped and polished in one pass. Good work has a crisp line where brushed metal meets polished metal, with no blur.
- Dial print. Check the logo, the text weight, and the date window font. Crooked text, thick letters, or a date wheel with the wrong typeface are the first things anyone notices up close.
- Lume. Charge it under a lamp for thirty seconds. It should glow even and fade slowly. Patchy or fast-fading lume is a giveaway.
- Crystal and AR coating. The dial should stay readable at an angle. Heavy blue reflections look cheap.
- Bracelet and clasp. Look for even link gaps, a taper that matches the case size, and a clasp that closes with one clean click.
Red flags in a listing
- Stock photos only, no photos of the actual unit.
- No movement name, or a vague phrase like "high grade automatic."
- Weight listed as a range that swings by 40 grams or more.
- A price far below the rest of the market for the same build.
- No stated case diameter or lug width.
How to check before you buy
- Ask for dated photos of the exact watch, including the caseback and clasp.
- Confirm the movement family and the case diameter in writing.
- Compare the dial details against photos of the genuine reference.
- Ask about water resistance and whether the gaskets were greased.
- Check the return window and what counts as a defect.
One legal note
Selling counterfeit goods is illegal in the United States, and shipments can be seized by customs. That is worth knowing before you spend money, regardless of how good the replica looks.
The bottom line: ignore the 151. It is a shop label. The watch earns its price through its movement, its case work, and its dial, and those are things you can inspect in photos if you know where to look.