Quick answer

215.33.44.21.01.001 is an Omega reference number in the Seamaster Planet Ocean 600M family. Omega uses a seahorse, or hippocampus, as the Seamaster emblem, so "hippocampus replica" is a seller term for a fake Seamaster. The reference number is a case and movement code, not a model name.

Reading the number blocks

Omega reference numbers run in five blocks. Each block holds one attribute.

  • 215: product family. 215 maps to the Seamaster Planet Ocean 600M.
  • 33: case and strap material. Omega pairs a steel case with a non-metal strap in this block.
  • 44: case size class. Planet Ocean references in this block measure 43.5 mm across.
  • 21: movement family. Planet Ocean models in this block run caliber 8900.
  • 01.001: dial color and variant. 01 is black.

Check each block on the Omega catalog page for this exact reference. Sellers reuse reference numbers on watches that do not match them. One point I could not verify: the exact strap material tied to block 33. Confirm it at the source.

The genuine watch

The Planet Ocean 600M carries Master Chronometer certification from METAS. The test covers rate, magnetic resistance to 15,000 gauss, and water resistance to 600 m. Caliber 8900 uses two barrels and runs about 60 hours on a full wind. The case takes a domed sapphire crystal and a screw-in crown. Omega sells it through authorized dealers with a five-year warranty.

Where replicas differ

Replica copies of this reference show gaps in four places.

  • Movement. Most fakes use a Chinese or Japanese automatic or a quartz module. None hold METAS certification. Beat rate and power reserve do not match.
  • Case and finishing. Bezel inserts, crown guards, and lug shapes shift between factories and between batches from the same factory.
  • Crystal and dial. Anti-reflective coating on a replica is thinner or absent. Lume fades sooner.
  • Water resistance. A fake stamped 600 m has no pressure test behind the number. Do not swim with one.

Legal note

Omega is a brand of the Swatch Group. The seahorse emblem, the Seamaster name, and the reference number are protected marks. Import of counterfeit watches into the United States is illegal, and Customs and Border Protection seizes shipments. Selling a counterfeit as genuine is fraud. A buyer gets no warranty, no service parts, and no recourse.

Checks before you buy

  • Ask for a photo of the rotor and the movement number.
  • Ask for a pressure test result, not a claim of depth rating.
  • Compare the reference number block by block with the Omega listing.
  • Treat a price far below retail as a signal, not a bargain.