What "fake Globemaster 40mm" usually means
Most people searching that phrase are chasing one watch: a replica of the Omega Constellation Globemaster, the pie-pan dial model Omega introduced in 2015 as its first Master Chronometer. The number in the keyword comes from seller listings, not from Omega. The genuine case measures 39.9mm across, so 40 is rounding. When a listing shows calipers in the photo holding a hard 40.0, I look at the rest of the pictures before anything else, because that spec sheet gets copied between models.
Dial and date are the first giveaway
The Globemaster dial is a true pie pan. It steps down from the outer minute track to a flat inner field, and the step is sharp under a fingernail. Cheap copies press a shallow dish instead, and the step turns soft under angled light. The applied OMEGA wordmark and the Constellation star should sit proud of the surface with crisp edges. On lower-tier reps they are glued on slightly crooked or sit too flat.
The date window belongs at 6 o'clock on this reference. A replica with the date at 3 is not a Globemaster, no matter what the title says. Check the font too. The genuine date disc uses a slim, tall numeral set that Omega has kept consistent.
The bezel and crystal
Steel Globemasters use a fluted bezel in tungsten carbide, a material harder and denser than the case steel. Replicas almost always use polished steel. It looks close in photos and reads slightly warmer in person, and it picks up scratches faster. The crystal is box-domed sapphire with anti-reflective coating on both faces. On budget copies the coating is on top only, so the dial greys out at an angle instead of staying dark.
Movement is where the gap stops closing
The real Globemaster runs the 8900 or 8901, a twin-barrel co-axial automatic with a 60-hour reserve, a jumping hour hand for travel, and resistance to 15,000 gauss. It carries METAS Master Chronometer certification, which is tested on the cased-up watch, not just the bare movement.
No replica reproduces that. First-copy Globemasters use a Miyota 9015 or a decorated Chinese automatic. They run around 40 hours, they have no co-axial escapement, and they hold no certification. The tell I check first: pull the crown to the time-setting position and move the hour hand alone. Genuine 8900 movements jump the hour in one-hour steps without stopping the seconds. Most replicas cannot do it, or they stop the movement to change the date.
Rotor engraving is another spot. Real Omega rotors are engraved and filled. Copies are usually laser-etched or printed, and the lettering has no depth when you tilt it in light.
Size, weight, and wrist feel
Genuine dimensions: 39.9mm wide, roughly 12.7mm thick, 20mm lug width, 100m water resistance, sapphire caseback. Replicas often land at 13.5mm or more because the movement and spacer stack is thicker. Some cheap copies feel heavier than the real thing for the same reason, so weight alone is a poor test. Tungsten carbide is denser than steel, so a genuine steel Globemaster feels bottom-heavy in the bezel area while a copy feels evenly weighted.
Honest expectations
A good first-copy Globemaster can pass at arm's length in a room. It will not pass a loupe, a magnet test, or a METAS card lookup, and Omega will not service it. Prices for the better copies sit in the low hundreds, which is the range where the case finishing and dial print stop improving. If someone offers you a "Globemaster" at four figures and calls it genuine, that is a different transaction with different legal exposure, and the caseback number is the first thing to verify against Omega.