Short answer: the best fake IW371634 is the one that copies behavior, not paperwork. That means a case with the right curve and thickness, a dial where subdial spacing and printing hold up under a loupe, and a chronograph that starts, stops and resets like a column-wheel movement should. Factory names, "1:1" stickers and fancy boxes tell you nothing about any of that.
What the IW371634 actually is
The ref. IW371634 sits inside IWC's Portugieser Chronograph family. The modern 3716 generation runs about 41mm across, roughly 13mm thick, with a slim bezel, leaf hands, applied numerals at 12 and 6, and two subdials: chronograph minutes at 12, running seconds at 6. Inside is the in-house calibre 69355, a column-wheel chronograph with around 46 hours of power reserve. Dial and strap variants shift by year and market, so pull the exact spec from IWC's own product page for that reference before you judge any replica against it. Guessing gets you nowhere.
Case and crystal, the first thing I check
Replicas get caught here more than anywhere else. Look at the lug tops and how they roll into the caseband. Cheap copies machine a flat shelf and it reads wrong from arm's length. Check case height too, since thin movements cost money and a lot of fakes pad the case to hide a thicker movement. The crystal should sit close to flush with the bezel, not rise like a dome. Run a fingernail across the edge. If it catches, walk.
Dial tells that survive a phone camera
- Subdial spacing: on the genuine layout the two subdials sit close to the center line. Many fakes push them outward to fit a donor movement.
- Printing weight: the minute track should be fine and even. Blobby or doubled printing means pad printing done fast.
- Applied numerals: sharp facets, no glue haze around the feet.
- Hands: leaf shape with a clean center crease, and the chrono seconds hand should sit dead on zero when reset.
- Color: silver-white and blue dials are the hardest to match. Ask for photos in daylight, not studio light.
Movement, where most of them fall apart
Two families show up in this reference. Entry builds use a basic automatic with a chrono module bolted on, and the module is the weak link. Better builds use a clone or a heavily reworked 7750-type movement, which gets you closer to the right pusher feel. One concrete test: start the chronograph and let it run past 30 minutes. The counter at 12 should stop at 30 and stay there. Plenty of fakes keep counting because the subdial is a 12-hour totalizer dressed up to look right. Another test: press the pushers. They should feel firm with a short travel, not spongy or gritty.
Ask the seller these before paying
- A short video of the chronograph starting, stopping and resetting to zero.
- A close-up of the caseback and the movement through it, if it has a display back.
- The exact movement name and whether a service part is available.
- Return window and who pays shipping on a return.
- What happens if customs seizes the parcel.
Red flags
- Only stock photos, no image of the actual unit.
- "Swiss made" claims on a watch priced in the hundreds.
- No movement photo on a display-back model.
- Crypto-only payment with no return policy.
- Prices far below the normal band for that build. Something got cut.
What pricing looks like
Rough bands as of now: a couple hundred dollars buys an entry automatic with thin finishing and a module chrono. The middle band, call it $350 to $600, is where correct dial layout and a usable movement show up. Above that you are paying for clone movement work and better case finishing, and you are getting close to what a legitimate homage watch costs with a real warranty. No replica holds value, and none comes with service support from the maker.
The legal side, briefly
In the US, importing or selling counterfeit goods is illegal, and parcels do get seized. Buying for personal use sits in a gray zone, but you carry the loss if the package disappears. Factor that risk into the price before you decide the cheap listing is a bargain.