Short answer
A fake Omega Constellation 131 copies the steel Constellation line that Omega launched in 2020. The real watches run Master Chronometer calibres at 25,200 vibrations per hour, carry an 8-digit reference on the case back, and ship with a METAS card. Most fakes fail on the beat rate, the date font, or the depth of the bezel engraving.
What reference 131 covers
131 is the base group for current steel Constellation models. Case sizes are 35 mm and 39 mm, and there is a 41 mm version under 131.23. A full reference reads like 131.10.39.20.01.001. The second group marks the metal, so .10 is stainless steel and .20 is steel with gold. The remaining groups change with dial color and bracelet. Two watches can share the first six digits and differ in dial and hands, so the reference alone proves nothing.
Movement
Steel 131 Constellations use Calibre 8800, or 8801 when the rotor and bridges carry gold. Both run at 25,200 vph, which is 3.5 Hz. Power reserve is 55 hours. The escapement is co-axial, magnetic resistance is rated to 15,000 gauss, and METAS certifies each movement as a Master Chronometer.
Fakes use Miyota 9015, Seiko NH35, or a decorated Chinese clone. Those run at 28,800 vph (4 Hz) or 21,600 vph (3 Hz). Put the watch on a timegrapher before you buy. A 4 Hz sweep on a watch sold as an 8800 is a mismatch you can measure in ten seconds. Rotor engraving on fakes is shallow, and the arabesque Geneva waves on the bridges are stamped rather than cut.
Case back and numbers
Current 131 models have a sapphire case back. The rim carries CONSTELLATION, the full reference number, and the serial. Omega serials are 8 digits. The reference on the case back must match the dial layout, the bezel style, and the bracelet. Fakes reuse one number across a whole production run, or print a reference that belongs to a different dial color.
Bezel and dial
The 35 mm and 39 mm steel models have a polished steel bezel with engraved Roman numerals. The cuts are deep and filled. The dial is domed with a sun-brushed finish, and the applied indexes are faceted with polished edges. The date sits at 6 o'clock in a metal frame.
On fakes the Roman numerals sit shallow and look printed. The date disc font is wider than the dial printing, and the date sits off center in the window. The case claws at 3 and 9 are cast as one piece with the case on fakes, so the line where the claw meets the bezel is missing.
Bracelet and clasp
The bracelet has polished center links and brushed outer links. The clasp is a butterfly type with the Omega symbol on the cover. Genuine engraving is cut with sharp edges and even depth. Fakes show stamped marks, rounded edges, and end links that do not sit flush against the case.
Paperwork and price
Every current Omega ships with a Master Chronometer card, a pictograms card, and a warranty card. The numbers on the cards must match the case. Check the METAS number against the movement serial.
Steel 131 references list above USD 5,000 at authorized dealers. Gold and two-tone versions cost more. A sealed watch at a third of list price is not a genuine watch.
Quick checks
- Beat rate: 3.5 Hz for calibre 8800.
- Reference on the case back matches the dial and bracelet.
- Date font and alignment at 6 o'clock.
- Bezel numerals cut and filled, not printed.
- Clasp engraving depth and edge finish.
- METAS card number present and matching.