Short answer: 525.10 is not a reference number you will find in Omega's Globemaster catalog. Omega builds references in its own PIC format, and the 39 mm steel Globemaster models sit under codes that begin 130.33.39 for strap versions or 130.30.39 for bracelet versions, followed by dial and variant digits. When a listing leads with 525.10, that figure is usually the seller's own stock number, a warehouse code, or a mash-up of two unrelated watches. Treat it as a label on the listing, not as identification.

What the genuine Globemaster actually is

Omega launched the Globemaster in 2015 as the first watch certified under the Master Chronometer program. It is a 39 mm steel Constellation with a stepped pie-pan dial, a fluted bezel cut from tungsten carbide, and a Co-Axial calibre 8900 inside. Power reserve runs about 60 hours, and the movement is rated to keep time in a field of 15,000 gauss, which is far beyond what a normal daily wearer will ever encounter. A 41 mm Annual Calendar version followed later.

Why Globemaster copies are thinner on the ground

Counterfeiters follow volume. Submariner and Daytona copies get made by the tens of thousands because the originals are instantly recognizable on any wrist. The Globemaster is a quieter watch, and the details that make it expensive are the details that are expensive to copy. That combination means fewer copies exist, and the ones that do tend to be coarser than the same factory's dive watch output. If you are comparing listings, the Globemaster is not the model where the counterfeit trade puts its best work.

How to check one in your hand

• Master Chronometer card. Every certified Globemaster ships with a card carrying an access code tied to that specific movement. Typing the code into Omega's site pulls the actual test results. Copies come with a printed card, but the code resolves to nothing.
• Bezel material. Tungsten carbide reads grey and slightly matte next to polished steel. Copies usually use bright chrome steel or a plated ring that wears through at the edges.
• Dial step. The pie-pan profile should show a clean, even break between the flat center and the outer ring, with the minute track printed flat on the raised section.
• Case back. The Constellation observatory medallion should be stamped sharply, with the stars distinct and evenly spaced.
• Movement. Calibre 8900 uses a free-sprung balance with a silicon hairspring. Copies show a regulator arm and a decorated rotor with engraving that does not match Omega's pattern.

What you give up either way

A counterfeit Globemaster has no factory service path, no warranty, and effectively no resale market. Omega will not service a fake, and independent watchmakers often decline once they open the case. There is also the legal side: importing counterfeit trademarked goods into the United States is unlawful, shipments are subject to seizure by U.S. Customs and Border Protection, and buyers can face penalties. That risk sits on your side of the transaction, not the seller's.

If the look is what you want

Buy a used genuine Globemaster on the secondary market, or look at brands that make their own designs in a similar vintage Constellation style. Both routes give you a watch that can be serviced, insured, and sold later. A stock code like 525.10 will not do any of that for you.