Reference 212.30.41.20.01.003 is a 41 mm Omega Seamaster Diver 300M in stainless steel. It uses a Co-Axial caliber 2500, a ceramic bezel insert, and a 300 m depth rating. A fake fails on four points: the caseback markings, the movement, the bezel and dial finish, and the paperwork that ties the serial to the watch. Photos answer none of these. A loupe and a caseback opener answer most of them.
Start with the reference and serial
The 212 family covers several Seamaster Diver 300M variants. Confirm the full number, not just "212". The last blocks of the reference encode case size, dial color, and bracelet. A watch sold as 212.30.41.20.01.003 with a blue dial is a mismatch before any other check.
Omega puts an 8-digit serial on the watch and repeats it on the movement. The warranty card carries the same serial. All three must match. Placement changes between production years, so compare stamp position and font against a known example from the same year. Ask an independent watchmaker to open the case and photograph the movement and the inside of the caseback.
Fake Omega 212 vs. Omega Comparison Review
Check the caliber 2500
The genuine movement runs at 25,200 vibrations per hour, 3.5 Hz, with a 48-hour power reserve. A timegrapher shows that rate in seconds. Many replicas use a 28,800 vph clone, and the reading exposes them. Look at the rotor engraving, the "Co-Axial" text, and the movement serial. Genuine finishing is fine and consistent. Replica finishing is stamped, not cut, and the lettering sits shallow.
Bezel, dial, and case details
The bezel is unidirectional with a ceramic insert and a white scale. The triangle at 12 should line up with the dial marker. Lume on the pip sits flush. The dial has applied indices in metal frames, clean print, and a date window at 3 with a matched font. Look at the helium escape valve at 10 and the crown guards. Check the caseback relief and the depth engraving. Soft edges and glue around the lume are replica signs.
Papers, box, and price
A full set is a warranty card, pictogram card, card holder, manual, hang tag, and inner and outer box. The card serial must match the watch. Service receipts add value but are easy to fake in isolation. Most secondhand steel 212 references trade between about $2,000 and $3,500. Offers far under that range need an explanation.
What a visual check cannot do
Good replicas pass a photo review. Only the movement, the serial checks, and a watchmaker's inspection give a firm answer. If the seller refuses an inspection or a serial check with an Omega service center, treat the watch as unknown. Some details in this guide depend on production year. Verify reference data against Omega's own documentation for the exact number you are buying.