Top pick for most buyers: an automatic chronograph replica of the Speedmaster 323.10.40 with a 40 mm steel case, a date window in the correct position, and a steel bracelet with a solid clasp. The five criteria behind that pick are case size and thickness, dial layout and date placement, bracelet construction, movement type, and how the chronograph pushers feel. Those five points separate a watch you can wear every day from one that stays in a drawer.
What the reference number tells you
Omega reference codes carry information in blocks. In 323.10.40 the 10 points to a stainless steel bracelet, and 40 is the case diameter in millimeters. The genuine watch is a 40 mm stainless steel automatic chronograph with a date, which wears smaller than the 42 mm Moonwatch most people picture when they hear the word Speedmaster. That single number changes what you should look for in a replica, because a 42 mm case attached to a 40 mm reference listing is the first thing to rule out.
Criterion one: case size and thickness
Ask for a measured diameter at the bezel rather than the advertised one. A 40 mm chronograph should sit close to 40 mm across the bezel, with a case height that stays under roughly 14 mm. Replicas that borrow a bulkier case often land at 42 mm or push past 15 mm thick, which changes how the watch sits under a shirt cuff. Check lug width as well: 19 mm or 20 mm spacing with the wrong spring bars turns every strap change into a fight.
Criterion two: dial layout and date placement
Subdial spacing is the giveaway most people miss. The chronograph subdials need to sit at the correct distance from the center, and the date window needs to line up with the reference. On a correct build the date aperture sits in the same position as the genuine watch, with a date disc whose font matches the dial printing. Common faults include a date window set too far to one side, subdial hands that refuse to zero out, and printed text that runs thicker than the original.
Criterion three: bracelet and clasp
The bracelet carries a large share of the perceived quality. Look for solid end links that meet the case with no gap, a clasp that closes with a firm click, and links that hold their tension after adjustment. Hollow links and stamped clasps rattle, and a rattle is audible in a quiet room. If the seller photographs only the dial, ask for images of the clasp interior and the end link fit.
Criterion four: movement and chronograph function
An automatic movement with a working chronograph is the point of the exercise. Start the chronograph, let it run a minute, stop it, reset it, and repeat. The seconds hand should sweep rather than tick, and the pushers should travel with a defined click at the end. A quartz movement is easy to spot: the large seconds hand jumps once per second, which no mechanical chronograph does. Subdials that never move are decoration, not a function.
Criterion five: crystal, lume, and finishing
A sapphire crystal with a clean anti-reflective coating keeps the dial readable in daylight. Lume on the hands and hour markers should charge after a few seconds under a light and fade at a similar rate across the dial. Brush and polish lines should meet at crisp edges instead of blurring into each other. These details seldom show in a hero photo, so ask for a close image of the case flank and the crystal edge.
The three tiers and who each one suits
Quartz display piece
- Pros: lowest entry cost, keeps time without winding, light on the wrist.
- Cons: ticking seconds hand, decorative or wrong subdials, thin case feel, weak clasp.
- Best for: a costume piece worn a few times a year, or a low-risk test before spending more.
Entry automatic with a working chronograph
- Pros: sweeping seconds, functioning pushers, decent weight and balance, easy to find.
- Cons: date position or subdial spacing may be off, thickness often too generous, bracelet may use hollow links.
- Best for: daily wear, office use, and anyone who wants the chronograph to actually work.
Higher-tier automatic clone
- Pros: closer case profile, cleaner dial printing, solid end links, better crystal and lume.
- Cons: highest cost of the three, limited stock, and a replica movement that still needs servicing like any automatic.
- Best for: collectors who want the closest match and will inspect the watch in hand.
Use-case recommendations
For one watch worn most days, take the entry automatic with a working chronograph and a true 40 mm case. It covers the reference look, keeps the function intact, and leaves room in the budget for a service later. For a display or collection piece that will be handled and compared side by side, the higher tier earns its price through case profile, dial printing, and bracelet fit. For occasional wear or a first taste of the reference, a quartz version is honest about what it is, provided you accept the ticking hand.
Red flags before you pay
- An advertised diameter of 42 mm on a listing for a 40 mm reference.
- No photo of the chronograph running, or a photo with every subdial hand parked at zero.
- Stock images that match several listings word for word.
- No return window, or a seller who refuses a request for a wrist shot next to a tape measure.
Bottom line
Match the replica to the reference rather than to the badge. A 40 mm case, a correctly placed date, a working chronograph, and a bracelet that does not rattle will read as the watch you asked for. One note on honesty: a replica should never be sold or passed on as a genuine Omega, and any listing that hints otherwise is a seller to avoid.