Answer First

The "5000" in listings points to the Blancpain Fifty Fathoms Automatique reference family. Those watches are 45 mm across and rated to 300 m. Genuine examples run on the caliber 1315 with a 120-hour power reserve. Replicas of that reference sell for $150 to $600. They use a 40-hour Asian automatic movement. No replica matches the movement, the power reserve, or the pressure rating.

What the Name Means

Fifty fathoms is 300 feet, or 91.44 m. Blancpain used that depth as the model name in 1953. The case rating is 300 m, which is deeper than the name requires.

Reference numbers in this family start with 5000 or 5015. Sellers use both numbers for the same watch. The case back engraving decides which reference a piece is. Ask for a photo of the case back before you compare prices.

Genuine Specs to Compare

  • Case: 45 mm steel or titanium, about 15.4 mm thick
  • Lug width: 23 mm
  • Bezel: unidirectional, sapphire insert with lume under the sapphire
  • Movement: caliber 1315, automatic, 227 parts, 35 jewels
  • Rate: 28,800 vph (4 Hz)
  • Power reserve: 120 hours
  • Water resistance: 300 m
  • Crystal: domed sapphire

Where Replicas Differ

  1. Crystal. Many replicas ship with mineral glass. It scratches, and the edge shows a different curve.
  2. Bezel insert. Genuine uses sapphire. Replicas use sapphire on top grades and printed metal or acrylic on low grades.
  3. Bezel clicks. Genuine has 120 positions. Replicas have 60 to 90, or a friction ring with no clicks.
  4. Power reserve. Genuine runs five days. A Miyota 9015 or 2824 clone runs 38 to 42 hours.
  5. Case thickness. Replicas measure 0.5 mm to 1.5 mm thicker. The gap shows at the lugs.
  6. Crown and threads. Low grade crowns strip after a few months of use.
  7. Lume. Genuine uses Super-LumiNova. Low grade replicas fade in 20 minutes.

Water Resistance

Replica listings claim 30 m to 100 m. Those numbers come from the seller, not from a test. Gaskets are the weak point. A local watchmaker can pressure test a case for $30 to $60. Do not swim with an untested replica. Salt water and chlorine reach the movement through the crown tube.

Price Bands

  • Low grade: $60 to $150. Mineral glass, printed bezel, quartz or low grade automatic.
  • Mid grade: $150 to $350. Sapphire crystal, 9015 movement, steel case.
  • Top grade: $350 to $600. Decorated movement, sapphire bezel, closer case dimensions.
  • Genuine steel Fifty Fathoms Automatique: about $15,000 to $20,000 at retail.

Legal Status in the US

Counterfeit watches are illegal to import into the United States. US Customs and Border Protection can seize a shipment and destroy it. Trafficking in counterfeit goods falls under 18 U.S.C. 2320. A first offense carries up to 10 years in prison and a $2,000,000 fine for an individual.

Checklist Before You Buy

  • Ask for the movement name and the jewel count.
  • Ask for a photo of the case back engraving.
  • Ask for a 10-second video of the seconds hand.
  • Ask for the pressure test result and its date.
  • Ask for the return window in writing.

What Is Not Known

Replica batches change without notice. Two watches from one listing can differ in case size by 0.5 mm. Factory names used by sellers are labels, not confirmed makers. No public data exists on unit counts.