What 291 Means in a Replica Seamaster 300M Listing

Omega does not use 291 as a Seamaster 300M reference. Genuine Seamaster 300M references run to eight digits, such as 210.30.42.20.03.001. The digits 291 appear in two places: the 1957 Seamaster 300 caseback stamped CK2913, and stock numbers that sellers assign to their own inventory. Treat 291 as a seller SKU. It carries no information about the watch.

Genuine Specs to Compare Against

  • Case: 42 mm diameter, 13.6 mm thick, 20 mm lug width on the current 210.30.42 line.
  • Movement: Omega Co-Axial Master Chronometer 8800. Power reserve 55 hours.
  • Water resistance: 300 m. Helium escape valve at 10 o'clock.
  • Crystal: sapphire front. Caseback is sapphire or steel, depending on version.
  • Bezel: ceramic insert with an enamel or Liquidmetal dive scale.

Measure any replica against those numbers. A 41 mm case or a 22 mm lug width does not match the original.

Replica Tiers and What Each One Uses

  1. Quartz, $40 to $90. Miyota or unbranded quartz. Case is too thick. The helium valve is a fixed crown.
  2. Entry automatic, $90 to $180. DG2813 or Miyota 8215. Date font is wrong. Lume fades within 20 minutes.
  3. Mid tier, $180 to $400. Seiko NH35 or a clone ETA 2824. Dial print is closer. Bezel action is loose.
  4. High tier, $400 to $800. Decorated clone 8800. Case profile is close. No part interchanges with Omega.

These price bands move. Check current listings for the date of the quote.

Known Tells

  • Date window position and numeral font.
  • Bezel insert markers. Omega uses enamel or Liquidmetal. Replicas use paint.
  • Crown guard shape, and the helium escape valve crown at 10 o'clock.
  • Caseback engraving depth and the seahorse outline.
  • Clasp stamping and the count of micro-adjust holes on the bracelet.

Photos at 3x zoom show most of these. Ask for a video of the seconds hand sweep before payment.

Water Resistance Claims

A replica marked 300 m has not been pressure tested. Gaskets on low tiers are dry or absent. Do not swim with one. Do not shower with one. The helium escape valve on most replicas is a dummy crown with no gas path, so it does nothing at depth.

US Legal Position

Counterfeit watches are illegal to import and to sell in the United States. 18 U.S.C. 2320 covers trafficking in counterfeit goods. CBP seizes shipments and can destroy them. The personal-use exemption for one item does not cover counterfeit merchandise. Selling a replica as genuine is a separate violation under the Lanham Act. Penalties include fines and prison time. This is not legal advice.

Questions to Ask a Seller

  1. Movement make and model number.
  2. Case diameter, thickness, and lug width in millimeters.
  3. Photos of the actual unit, not stock images.
  4. Return window and who pays return shipping.
  5. Payment method and chargeback terms.

If a seller cannot answer items 1 and 2, the listing is a stock photo operation. Unknown sellers with no return policy carry the highest risk of a wrong or non-working unit.