Answer

The Omega Seamaster Diver 300M reference 210.30.42.20.03.001 is a 42mm stainless steel dive watch. It has a blue ceramic dial with laser-engraved waves. The genuine watch uses the Omega Co-Axial Master Chronometer Calibre 8800. Water resistance is 300 meters. Replicas of this reference come in grades. Top-grade replicas cost $300 to $500. They use a clone of the 8800 or a decorated ETA 2824. No replica has Master Chronometer certification.

Genuine specifications

  • Case diameter: 42mm
  • Case thickness: 13.6mm
  • Lug-to-lug: 49.9mm
  • Water resistance: 300m
  • Movement: Omega 8800, 55-hour power reserve
  • Magnetic resistance: 15,000 gauss
  • Crystal: sapphire, anti-reflective on both sides
  • Bezel: ceramic with white enamel diving scale
  • Helium escape valve at 10 o'clock
  • Date at 6 o'clock

Replica grades

Low-grade replicas use quartz movements and mineral glass. Case dimensions differ from genuine. Dials are painted. Mid-grade replicas use automatic movements, 316L steel, and sapphire glass. High-grade replicas use clone movements, correct case dimensions, and ceramic bezels. Some high-grade replicas use 904L steel. Omega uses 316L steel for reference 210.30.42.20.03.001. So a 904L replica is not correct for this reference.

Differences

  • Dial waves: genuine has laser engraving. Replicas have printed waves or engraving depth less than 0.1mm.
  • Lume: genuine uses Super-LumiNova. Replica lume glows for 2 to 4 hours. Genuine lume glows for 8 hours.
  • Helium escape valve: genuine is conical. Replica may be flat.
  • Crown logo: genuine is raised. Replica may be stamped.
  • Caseback: genuine has a wave pattern and engraving depth of 0.3mm. Replica engraving depth is 0.1mm.
  • Bracelet: genuine has a diver extension and micro-adjust. Replica may have hollow end links and sharp edges.
  • Movement: genuine 8800 has a silicon balance spring and 15,000 gauss resistance. Replica movements lack these.

Checks for buyers

Check the date font. Genuine date font has thin strokes. Replica date font has thick strokes. Check the bezel action. Genuine bezel has 120 clicks with no backplay. Replica bezel may have backplay or 60 clicks. Check the crown threads. Genuine crown screws down with 3 turns. Replica may have 1 or 2 turns. Check the lume. Charge the lume with a light for 30 seconds. Genuine lume glows for 8 hours. Replica lume glows for 2 to 4 hours. Check the movement. Genuine 8800 has a sweep at 25,200 vibrations per hour. Replica 2824 has 28,800 vibrations per hour. A timegrapher can show the difference.

Price

Genuine 210.30.42.20.03.001 costs $5,400 on a steel bracelet. Replica prices: low-grade $50 to $100, mid-grade $150 to $250, high-grade $300 to $500. No replica holds value. No replica has a warranty from Omega. Servicing a replica movement is difficult. Parts are not available from Omega.