The replica IW371758 is a copy of the IWC Portugieser Chronograph, a 41mm stainless steel watch with two subdials, a narrow polished bezel, and a leather strap. Good copies match the case profile, dial printing, and hand shape. The movement inside is a third-party chronograph caliber, not an IWC-made one.
What Is the IW371758?
IW371758 is a reference in the IWC Portugieser Chronograph line, a family built around a dress-watch case with a stopwatch function. The series goes back to the 1930s Portugieser wristwatches, which put pocket-watch movements into large round cases.
Reference numbers in this line change with dial color, strap, and case metal, so one number points to one exact combination. That matters for replicas, because a factory that gets the dial right may still use the wrong strap color or hand finish.
Real specs to compare against:
- Case: stainless steel, about 41mm across and 13mm thick
- Bezel: polished, narrow, no markings
- Dial: two subdials (running seconds at 6, chronograph minutes at 12) with a fine printed minute track
- Hands: leaf-shaped, polished, slim
- Crystal: domed sapphire with anti-reflective coating
- Movement: IWC caliber 69355, automatic, column wheel, about 46 hours of power reserve
- Strap: alligator leather, 20mm at the lugs
- Water resistance: 3 bar (30m), which means splashes only
How Close Does the Replica Get?
Case and finish
Top replicas hold the case diameter within a fraction of a millimeter. Thickness is where most fall short: a build with a modular chronograph movement runs about 1mm deeper, and that shows under a shirt cuff.
Study the lug profile and the line where the brushed case band meets the polished bezel. Budget copies leave that edge soft and rounded, which is the fastest tell in person.
Dial and hands
Dial printing decides most of the impression. The brand name and "SCHAFFHAUSEN" should sit crisp, with even spacing and no ink bleed at the edges.
Subdial rings should be thin and level, and the hands should reach the minute track without overhang. Cheap builds use hands that run short or sit flat under the crystal.
Movement
Most IW371758 replicas run a modified Valjoux 7750 pattern automatic, which gives you the chronograph function and the two-register layout. The trade-off is extra thickness and a rotor that winds in one direction, unlike the bi-directional winding of the real caliber 69355.
Some builders fit a hand-wound chronograph caliber instead. That version loses the automatic rotor but sits closer to the original case profile.
Strap and clasp
Factory straps are the weakest part on nearly every replica. The leather feels stiff, the stitching runs thick, and the buckle edges are sharp. A replacement strap in the right 20mm size is the cheapest upgrade you can make.
What Should You Check Before Buying?
- Ask for the case thickness in millimeters, not a description.
- Request angled photos of the dial so you can see whether the printing sits flat or raised.
- Check the gap between the two subdials. It should look even and centered.
- Look at the caseback engraving for depth and clean lettering.
- Confirm the crystal is domed sapphire with an anti-reflective tint, not flat mineral glass.
- Inspect the crown for a signed cap and crisp knurling.
- Ask for a short video of the chronograph start, stop, and reset.
Which Movement Sits Inside?
- Automatic 7750 pattern: strong, easy for a watchmaker to service, but adds thickness.
- Hand-wound chronograph: slimmer case, needs winding every day or two.
- Quartz: thin and cheap, but the seconds hand ticks and the pushers feel dead. Skip it.
Ask the seller for the movement name before you pay. A seller who cannot answer that question is reselling boxes, not watches.
What Do Replica IW371758 Watches Cost?
Prices vary by seller, but the market splits into three bands. Budget builds use mineral glass, stamped hands, and a rough dial print. Mid builds add sapphire, better case finishing, and a movement worth servicing. Top builds focus on case profile, dial accuracy, and small details like the crystal dome and crown shape.
Spend in the top band only if the seller sends real photos of the exact watch you will receive. Stock photos from the factory catalog tell you nothing about the unit in the box.
Common Flaws to Avoid
- Misaligned chronograph hands that do not reset to zero
- Oversized or undersized crown
- Mismatched letter spacing in the dial text
- A caseback that sounds hollow when tapped
- Strap stitching in a color that does not match the dial
- Screws that strip the first time you change the strap
Care and Maintenance
Treat a 3 bar rating as splash protection only. Take the watch off before swimming, showering, or washing dishes.
Have an automatic movement cleaned and oiled every few years if you wear it often. Keep the watch away from strong magnets, such as tablet covers and speaker housings, and rest it on a roll rather than loose in a drawer.
Hand-wound versions should be wound at the same time each day. Running a chronograph for long periods adds wear, so stop it when you are not using it.
FAQ
Is the replica IW371758 water resistant?
Most copies are rated 3 bar, the same as the original. That covers rain and hand washing, not swimming.
Does it use a real IWC movement?
No. Every replica uses a third-party caliber, often a modified 7750 pattern or a hand-wound chronograph.
How do I tell a top replica from a cheap one?
Case thickness, crystal material, dial printing, and strap quality separate the tiers. Start with thickness, since it is the hardest thing to fake.
What strap size fits?
The lugs take a 20mm strap. Measure the real lug width before ordering a replacement.
Is the chronograph function usable?
On mid and top builds, yes. Test the start, stop, and reset before you wear the watch.