Quick answer

A fake Aqua Terra 326.10.40 fails four checks: movement, dial grooves, caseback engraving, and serial numbers. The genuine watch runs Omega calibre 8500 or 8900 with a co-axial escapement at 25,200 vibrations per hour. Common replicas run an ETA 2824 clone or a Seagull ST2130 at 28,800 vph. A timegrapher shows the gap in under a minute.

What the 326.10.40 reference is

Omega builds the reference code from blocks. The 326 block marks the model line. The 10 block marks a steel case and steel bracelet. The 40 block marks case size. The 20 block marks the movement family. The 01 block marks dial color. The 001 block marks the version. This stem is a Seamaster Aqua Terra 150M in stainless steel, 40 mm case, 150 m / 500 ft water resistance, sapphire crystal, screw-down crown, three-link steel bracelet. Confirm the exact sub-reference against Omega's own listing before you compare anything.

Movement: the hard part to copy

Calibre 8500 has 39 jewels, two barrels, a 60-hour power reserve, a co-axial escapement, and a silicon balance spring. Master Co-Axial versions are rated above 15,000 gauss. The rotor carries a dark arabesque finish and the Omega logo. Replica movements show plain stripes, printed rotor text, and coarse chamfers. A fake jewel count reads 21 or 25, not 39. Genuine beat rate is 25,200 vph, which is 7 beats per second.

Dial and case checks

  • Teak lines: machined grooves with sharp edges. Light breaks across them at an angle. Printed lines stay flat.
  • Date window: cut edges, no burrs, date wheel matched to dial color, correct font.
  • Hands: faceted with polished sides. Lume sits level with the frame.
  • Caseback: sapphire display back, fine engraving, "150m/500ft" and the reference number in the right font.
  • Weight: about 150 g with the full bracelet. Copies land at 110 g to 130 g.
  • Serial: eight digits on the caseback and the same number on the movement. Omega can verify it at a service center.

Price math

Genuine 326.10.40 watches sold new for about $6,000 USD on a bracelet. Used examples trade between $3,000 and $4,300 in 2024 and 2025. Replicas sell for $150 to $600. A $400 "super clone" listing does not contain a co-axial escapement, a silicon hairspring, or Omega's 316L case finishing.

US law

Importing a counterfeit watch into the United States violates 19 U.S.C. § 1305. CBP can seize the shipment and destroy it. Trafficking in counterfeit goods carries penalties under 18 U.S.C. § 2320, including fines and prison time. The buyer holds the risk, not the seller.

Bottom line

Ask for a timegrapher reading, a photo of the movement, and the serial number. If any of the three is missing, treat the watch as a replica.