The short answer
A replica Constellation 131.90 is a copy of the modern Omega Constellation, the one with the polished claws at 3 and 9, the mono-bloc case, and the bracelet that runs straight out of the lugs. The 131 prefix sits in the current Constellation block of Omega reference codes, and the digits after it point to case size, metal, and dial. That makes 131.90 shorthand rather than a complete reference. If a listing shows only that number and nothing else, ask for the full eight-digit code before you send money.
What the real watch is
The modern Constellation took its current shape around 2009 and was cleaned up in 2020, when Omega flattened the bracelet and sharpened the case edges. Steel models sell in the mid four figures at retail, and gold, two-tone, and diamond-set versions climb from there. Sizes run from 25mm up to 41mm, with 36mm and 35mm doing most of the volume.
The details that matter on a rep are the ones you can see: a mono-bloc case, so there is no separate midcase seam; the two claws (Omega calls them griffes) that hold the bezel at 3 and 9; a bezel with engraved Roman numerals on several references; a dial with a fine silk texture; and the date at 6 with a small star above it. Inside, the 41mm runs calibre 8900 and the smaller sizes run 8800, both Co-Axial Master Chronometer and both rated to 15,000 gauss.
What good replicas get right
The better Constellation reps come from Omega-focused workshops rather than the big Rolex houses, and they get the silhouette right. Case profile, claw shape, and the way the first bracelet link sits flush against the case all read correctly from arm's length. You also get sapphire with inner AR, dial printing at the right weight, and a star that lines up over the date. On two-tone models the gold tone is close to Omega's warm yellow or Sedna shade when the watch is new.
Where they slip
Bracelet articulation is the biggest tell. Genuine Constellation links fold with almost no play, while a cheap rep rattles and shows uneven gaps between the polished center links and the brushed outer links. Dial texture is second: the silk pattern on a real dial has depth that catches light in bands, and on lower tiers it looks flat or too coarse. Third is the caseback, where the Observatory medallion and the surrounding text are shallow and the serial engraving uses the wrong font.
Smaller things I check: crown logo size, hand thickness, date window alignment, and clasp engraving that fades after a few months of desk wear. Silver silk dials hide texture flaws worst, so blue or black is the safer pick.
Movements
Ignore any label that says clone 8900. Nearly every Constellation rep runs a 28,800 vph automatic (Seagull ST2130, Hangzhou 6300, or an ETA 2824 pattern) dressed with a decorated rotor and bridges. The date at 6 is handled either by a repositioned date wheel or a modified movement, and that is the most common failure point. What I look for: smooth winding, a date that flips cleanly at midnight, and no rotor rub when the watch is shaken. A Swiss ETA 2824-2 costs more and is worth it if you plan to keep the watch for years. Quartz versions are cheap, but the sweep is wrong and the case is usually thinner than it should be.
Price tiers
- Under $150: quartz or low-grade automatic, flat dial, rattly bracelet. Fine as a beater, weak as a replica.
- $200 to $350: the sweet spot. Correct case, real AR, ST2130 or 2824 pattern movement.
- $400 to $650: best case and bracelet, sharper dial texture, tighter clasp, sometimes a Swiss movement.
Which size to pick
The 41mm is searched most, and it wears large because the case is nearly all dial and the bracelet does not taper at the lugs. The 36mm and 35mm are the safer everyday choices and match the smaller proportions the line is known for. Anything at 29mm or below is a women's size, and bracelet quality drops off fast down there.
Before you pay
- Ask for the complete reference and a photo of the caseback.
- Ask for the weight in grams. Gold and two-tone gens are heavier, and a plated steel rep will feel light.
- Ask for a movement photo with the balance visible, not a stock image.
- Confirm the link count and whether half links ship. The Constellation clasp has limited adjustment.
- Check the return window. A seller who will not take it back within a week is a pass.
When it arrives, have it pressure tested locally before you swim with it. Water resistance claims on a replica mean very little, whatever the listing says.