The top pick for a 40 mm fake Speedmaster is a manual-wind build on a Seagull ST19 chronograph movement with a domed sapphire or hesalite crystal, because that combination lets the dial keep the correct 3-6-9 subdial layout. Subdial placement is the first thing an experienced eye reads, and most cheap 40 mm chronographs fail it. The criteria used here are case geometry, movement architecture, crystal and dial printing, and bracelet plus caseback finishing. None of these watches are Omega products, and none carry Omega parts or service.
What 40 mm Means in This Market
The cataloged Speedmaster Professional Moonwatch is a 42 mm watch, and the older Speedmaster Reduced sits below that, so 40 mm is a compromise size rather than a factory reference. Sellers use the number for two different things: a true 40 mm case with a slim bezel, and a 42 mm case relabeled as 40 mm to catch search traffic. Ask for a photo with a ruler across the bezel and across the lugs before you commit. Lug-to-lug length decides comfort far more than the headline diameter, especially on a 6.5 inch wrist.
- Measure the bezel at its widest point, not the case flank behind it.
- Measure lug tip to lug tip, the number that decides whether the watch overhangs your wrist.
- Measure thickness, because chronograph modules add height fast.
- Confirm lug width, since 19 mm and 20 mm straps do not swap.
Criterion: Movement Architecture
The Moonwatch layout places running seconds at 9, the 30 minute counter at 3, and the 12 hour counter at 6. A Venus-derived movement such as the Seagull ST19 can be assembled into that 3-6-9 arrangement, which is why it shows up in the better 40 mm replicas. The Valjoux 7750 family puts its counters at 12, 6, and 9, forcing a subdial under the logo where a Speedmaster has open dial. Many 7750 builds also add a date at 3, another feature the Moonwatch never had.
- ST19 type: hand wound, correct 3-6-9 layout possible, slimmer case, less shock resistance.
- 7750 type: automatic, wrong subdial at 12 on most builds, thicker case, date window common.
- Quartz: lowest cost, running seconds tick once per second instead of sweeping, obvious under a loupe.
Criterion: Crystal and Dial Printing
Both hesalite and sapphire are defensible on a Speedmaster copy, since the real line has used both. What is not defensible is a flat crystal on a case that should carry a dome, or a sapphire with a heavy blue reflection across the dial. On the dial, compare wordmark height, the gap between the subdial rings and the center pinion, and lume color. Modern Moonwatch lume reads as a warm cream, not a bright green. The bezel insert should show crisp numerals and a finish consistent with the reference being copied.
Criterion: Bracelet, Pushers, and Caseback
Bracelet taper and end link fit separate a good 40 mm build from a rough one. Genuine Speedmaster bracelets taper toward the clasp; copies often stay wide and sit proud of the lugs. Pushers should be flat topped and align with the crown height. The caseback matters less on the wrist, but the engraving quality tells you how the rest of the case was finished, so photograph it under light before buying.
Option 1: Manual-Wind ST19 Build
Pros
- Keeps the 3-6-9 subdial layout, the strongest visual match.
- Thin case profile that wears close to the wrist.
- Hand winding suits the character of a Moonwatch.
Cons
- No automatic winding, so daily winding becomes routine.
- Lower shock resistance and fewer service options locally.
- Power reserve is shorter than a modern automatic.
Best for: buyers who want the closest dial and case proportions and do not mind winding.
Option 2: Automatic 7750 Build with Date
Pros
- Automatic winding and a date function for daily wear.
- Easy to find and easy to have serviced by a general watchmaker.
- Often the cheapest way to get a running chronograph at 40 mm.
Cons
- Subdial at 12 breaks the Speedmaster dial layout at a glance.
- Date window at 3 gives away the build immediately.
- Thicker case that sits tall on a small wrist.
Best for: someone who wants a wear-anywhere chronograph and cares more about function than dial accuracy.
Option 3: Quartz Budget Build
Pros
- Lowest entry cost and accurate timekeeping.
- Light, thin, and low maintenance.
- Fine as a travel beater you can lose without regret.
Cons
- Ticking running seconds are an instant tell.
- Dial printing is usually the weakest part of the build.
- Case finishing tends to be sharp at the lug edges.
Best for: a first experiment or a knockaround watch, not a daily driver.
Buying Checklist
- Ask for measured diameter, lug-to-lug, thickness, and lug width in writing.
- Request a straight-on dial photo to check subdial placement before anything else.
- Confirm which movement is inside, not just the phrase Swiss movement.
- Look at macro shots of the pushers, crown, and end links.
- Decide your size limit first, then your budget, and skip anything that fails both.