The short answer
There is no IWC reference IW938604 in the official catalog. The string shows up in replica dealer listings, where factories and sellers assign their own codes to a watch that copies a real IWC model. So when you search that number, what you are really asking is which version of this watch is built well enough to wear, and how to tell it apart from the junk. The answer comes down to four things you can check before you pay anyone: the movement inside, the weight and finish of the case, the dial printing and alignment, and whether the seller will show real photos of the actual unit they will ship.
Why the code is not the spec
IWC numbers its watches with the IW prefix followed by digits tied to a case and movement combination. A code that does not resolve on IWC's own site is a dealer tag, not a factory reference. Some sellers reuse one tag across two or three different models, and some invent new ones to make old stock look fresh. If a listing shows a code and nothing else, you have learned nothing. Ask for the base model instead: Pilot's chronograph, Portugieser, Ingenieur, Portofino. Case diameter, lug width, and dial layout follow from that, and those are the specs you can check against the genuine article.
What a good replica gets right
Movement
This is where the money goes. A mid-tier watch usually runs an Asian 7750 chronograph movement. It is a workhorse, but it can be noisy and rough at the pushers. Better three-hand builds use a clone of the ETA 2824 or a Seagull ST21 series. The top chronograph builds use a modified 7750 with cleaner bridge finishing and a smoother reset. What you want in practice: the chronograph starts without a lurch, the seconds hand sweeps rather than ticks, and the date flips near midnight instead of drifting for two hours.
Fake IW938604 Similar Watches: Closest Replica Matches
Case and finishing
Steel grade matters, but not as much as people claim. 316L is standard and fine. 904L shows up on the higher tiers and polishes to a slightly warmer sheen. More important is the hand work: brushed surfaces should hold a consistent grain direction, polished bevels should be crisp, and the line between the two should not look rounded off. Lug edges on a cheap case feel sharp. On a good one they feel broken and soft in the hand.
Fake IW938604: Why Buy a Replica and What to Inspect Before You Do
Dial and hands
Look at the printing through a phone macro lens. Good dials hold a sharp edge on the numerals, and the brand text sits level with no halo around it. Applied indices should sit flat and catch light the same way across the dial. On chronographs, check that the subdial hands rest at zero when reset. Hand length is a common shortcut: cheap builds use hands that fall a millimeter short of the minute track.
Crystal, strap, and clasp
Sapphire with a proper anti-reflective coating is what makes a dial look deep instead of flat. Single-sided coating is fine. If the glass looks milky at an angle, it is mineral or uncoated. Straps are easy to swap, so do not overpay for one. The clasp is worth a look though. A good deployant snaps shut with one clean click, and the logo engraving is cut rather than stamped.
Five checks before you buy
- Ask for a timestamped photo of the actual watch, not catalog renders.
- Ask which movement is inside and whether it is regulated before shipping.
- Check the weight. A 40mm steel watch should feel substantial. 90 grams means a hollow case.
- Get the return window in writing, and know who pays return shipping.
- Pay with a method that has a dispute process. A bank transfer offers you nothing.
Red flags
Prices far under the rest of the market, no photos of the movement, pressure to pay by gift card or crypto, and a 1:1 claim with no model name attached. Watch for sellers who list a dozen unrelated brands using the same photo set. That is a dropshipper, not a factory-connected dealer.
Legal and practical notes
A replica is not the genuine article and cannot be sold or passed off as one. Selling a counterfeit as genuine is a crime in the US and across most of the EU, and customs agencies seize shipments on a routine basis. If you buy one, treat it as a watch rather than an investment, and expect service and parts support to come from a local watchmaker rather than the brand. That is the honest tradeoff.