Answer first

The number 323.10.40 is the first three groups of an Omega reference. Full references in this family look like 323.10.40.40.01.001. The code reads as 323 for the Speedmaster model group, 10 for a steel bracelet and 40 for a 40 mm case. The last groups cover movement code, dial color and variant.

Replica versions of this 40 mm Speedmaster sell for $90 to $550. Price tracks the movement, not the case finish. A quartz copy sits at the bottom. An automatic copy with an A7750 chronograph movement sits above $220.

No replica in this family matches the genuine caliber. Check case diameter, subdial layout, date position and thickness before anything else.

Reference breakdown

  • 323: Speedmaster model group.
  • 10: stainless steel bracelet.
  • 40: 40 mm case diameter.
  • 40: chronograph movement code.
  • 01: dial color, black on most listings.
  • 001: variant code, including market of sale.

Sellers shorten the number to 323.10.40. Ask for the full string and a caseback photo before payment. Dial color and bracelet type change the last groups, and a short number hides that.

Genuine specs at a glance

  • Case diameter: 40 mm
  • Bracelet: steel, folding clasp
  • Complications: chronograph, date at 3 o'clock
  • Subdials: 12, 6 and 9 o'clock
  • Water resistance: 100 m on references in this group
  • Movement: Omega automatic chronograph caliber, year dependent

Genuine case thickness lands near 13 mm. Measure a replica at the caseback, not the crystal. Most automatic copies run 0.5 mm to 1.5 mm thicker because the A7750 is deeper than the original caliber.

Lug width on 40 mm Speedmaster cases is 19 mm on several sub-references. Measure the watch in hand. Lug width is a frequent fail point. A 20 mm bracelet on a 19 mm gap shows from two meters.

What copies get right

  • Dial printing and applied markers on better builds.
  • Subdials at 12, 6 and 9. Date window at 3.
  • Case diameter at 40 mm.
  • Sapphire crystal with anti-reflective coating on mid and top tiers.

What copies get wrong

  • Thickness. A7750 builds exceed 13 mm.
  • Bracelet end links. Gaps at the lugs, loose clasp tension.
  • Date font and window bevel.
  • Caseback engraving depth and letter spacing.
  • Weight. Steel copies land 10 g to 30 g under the original.

Movement options and prices

  1. Quartz, $90 to $150. Seconds hand ticks once per second. Subdials are decorative or tied to one motor.
  2. Seagull ST19 hand-wound, $150 to $250. Smooth sweep at 21,600 vph. No automatic winding, and the genuine watch winds from the rotor.
  3. A7750 automatic, $220 to $400. 28,800 vph, about 44 hours of reserve, working date and chronograph. Closest functional match on the replica market.
  4. Decorated A7750 in a top-tier case, $400 to $550. Plates get cosmetic finishing. The gear train is still a 7750 design.

Checks before you buy

  1. Ask for the full reference string and a caseback photo.
  2. Ask for a caliper photo of case diameter and thickness.
  3. Ask for a 10x photo of dial text and the date window.
  4. Ask how the chronograph resets. A pusher that needs two presses points to a quartz module.
  5. Ask about the bracelet. Request the clasp closed and end links seated.
  6. Get return terms in writing.

Unknowns

Omega production records tie this reference group to more than one caliber across years. Replica listings do not state which year they copy. Treat a claim of an exact year match as unverified unless the seller names the caliber and shows the movement.