Short answer: the replica IW371769 worth buying is a 41 mm steel build on an A7750-based automatic movement, with the chronograph counter at 12 and running seconds at 6, a domed sapphire crystal, applied numerals, and a measured thickness close to 13 mm. Anything that keeps running seconds at 9 o'clock, wears more than a millimetre too thick, or uses flat mineral glass is a costume piece, not a copy. The five criteria below are the ones that decide whether the watch survives daily wear, and each section ends with a plain recommendation.
Case proportions and wrist presence
The reference is a 41 mm Portugieser Chronograph on 20 mm lugs with a slim bezel, a polished flank, and a stepped case back. That geometry is what the eye reads from across a table, long before it reads any logo. Replicas cut from a generic 42 mm chronograph blank are the most common failure, and the extra millimetre shows at the lugs, where the strap path stops looking straight.
Pros
- 41 mm cases with 20 mm lugs accept standard aftermarket straps, so you can fit a better alligator band later.
- A correct lug curve sits flat on wrists from about 6.5 to 7.5 inches.
- Polished flanks and a brushed back match the reference finish split.
Cons
- Many builds measure 14 mm or more because the movement sits high in the case.
- Over-polished flanks round off the edge where the bezel meets the lug.
Buy it if: you wear the watch daily and care about silhouette. Ask for a caliper photo of the case thickness and walk away if the seller will not send one.
The 12 and 6 subdial test
This is the hardest detail to copy and the quickest way to spot a bad example. The Portugieser Chronograph places the chronograph counter at 12 and small running seconds at 6, which means the printed numerals 12 and 6 are removed to make room. A stock 7750 puts running seconds at 9, so a replica that has not been re-geared or modularised will show a seconds subdial on the left. That single tell disqualifies more listings than any other.
Pros
- Correct vertical subdial spacing gives the dial its tall, open look.
- The chronograph counter still sweeps and resets when the mechanism is properly converted.
Cons
- Conversions add friction, and cheap conversions make the chronograph hand stutter.
- Subdials sometimes sit a fraction too close together, which flattens the dial layout.
Buy it if: the seller can show the subdials running, with the seconds hand at 6 moving and the chronograph hand parked at 12.
Movement and thickness
The genuine watch runs IWC's automatic calibre 69355 with a 46-hour power reserve, and the case is built around it. Replicas use three broad tiers: an A7750 with a modified subdial train, a decorated A7750 with a rotor engraved to look like the original, and quartz versions that should be ignored. The first two keep the watch automatic and keep winding smooth. All of them are thicker than the movement they imitate, and that is where the case profile usually goes wrong.
Pros
- A7750-based movements beat at 28,800 vph, so the seconds hand sweeps smoothly.
- Parts and servicing are widely available, so a noisy rotor or a dry movement can be fixed.
Cons
- Rotor noise is common and audible in a quiet room.
- Engraved and striped finishing never matches the real movement architecture.
- Quartz listings look correct on a screen and feel wrong the moment you pick them up.
Buy it if: you want a watch you can wear and have serviced. Skip quartz entirely and ask what movement is inside before you pay.
Crystal, dial printing and hands
The reference uses a domed sapphire crystal with faint edge distortion, applied faceted numerals, and leaf-shaped hands. Replicas fail here in predictable ways: flat mineral glass with no distortion, printed numerals instead of applied ones, and hands that are too wide or too shiny. Dial text placement and the printed scale are worth comparing side by side against reference photography before you commit, because misaligned printing is visible at arm's length.
Pros
- A proper domed sapphire gives the dial depth and a soft edge highlight.
- Applied numerals catch light and read as metal, not paint.
- Leaf hands in the right finish keep the vintage dress feel intact.
Cons
- Mineral glass scratches and shows a hard, flat reflection.
- Printed numerals sit flush and look dull under direct light.
- Hand length is often slightly short, which throws off the dial balance.
Buy it if: the listing specifies sapphire and the photos show applied numerals with a raised edge.
Strap, buckle and hardware
The reference ships on alligator with a tang buckle, tapering from 20 mm at the lugs to 18 mm at the buckle. Rep strap leather is the first thing to degrade, and the buckle engraving is usually shallow. Both are cheap to replace, so treat them as consumables rather than deal breakers, but check the spring bars and lug holes, because a stripped lug hole cannot be repaired without welding.
Pros
- Standard 20 mm lugs mean a replacement strap costs little and transforms the watch.
- Quick-release spring bars make swaps easy if the seller includes them.
Cons
- Stock leather often stiffens within months and cracks at the lug bend.
- Buckle engraving is shallow and fades with polishing.
Buy it if: the lug holes are clean and the strap path sits straight on your wrist. Budget for one good replacement strap.
Pre-purchase checklist
- Confirm 41 mm diameter and request a measured thickness photo.
- Confirm the running seconds subdial sits at 6, not 9.
- Confirm sapphire crystal and applied numerals.
- Confirm the movement type and that it is automatic, not quartz.
- Ask for a short video showing the chronograph start, stop and reset.
- Check lug holes, crown threads and pusher action for slack.
A replica IW371769 that passes all six checks is a wearable copy of a dress chronograph that looks right on a shirt cuff and survives a normal week. One that fails the subdial test or the thickness check will never feel correct, no matter how good the photos are. Spend your money on the movement and the case first, and fix the strap afterwards.