The best replica IW371645 for most buyers is the stainless steel, leather strap version with a 41 mm case, a two register chronograph layout, and a modified automatic movement that drives the sub dials at 6 and 12. That pick holds up only if four checks come back clean: case proportions and case finishing, dial print and hand shape, chronograph movement type and reliability, and crystal, strap and clasp quality. Everything below explains those checks and how to apply them to the specific version you are looking at.
What the IW371645 Reference Is, and Why It Matters
The 3716 reference block covers a wide spread of the Portugieser Chronograph family. Dial colour, hands, case metal, bracelet option and date layout change from one number to the next, and the line was refreshed with a new case generation and in house movements. Before you compare copies, confirm the exact dial, metal and layout that the IW371645 label maps to on the official product record. A replica that matches the wrong reference is still the wrong replica, even if the build quality is high.
Two expectations to set up front. A replica is not a genuine watch, it carries no manufacturer warranty or service history, and its movement architecture will not match a genuine calibre. Treat every listing as a copy with its own spec sheet, not as an equivalent product.
Criterion 1: Case Proportions and Finishing
Case work is where cheap copies fall apart first. Measure the diameter, the lug to lug length, the thickness and the lug width yourself with calipers, then compare those numbers to the reference data. Chronograph copies built on modular movements often run thicker than the genuine case, which shows up as a tall slab on the wrist and a caseback that sits high. Check the lug curve, the bezel step, the crown and pusher profile, and whether the brushed and polished surfaces meet in a clean line.
Pros
- Correct diameter and lug width are easy to verify, so you can rule out weak listings fast.
- Case finishing quality is visible in ordinary light and does not require opening the watch.
- A well finished case hides small dial flaws and makes the watch wear closer to the reference.
Cons
- Extra thickness is common and hard to fix after purchase.
- Polished edges on low tier copies can look soft or over buffed.
- Crown and pusher threads wear faster on inexpensive builds.
Best for: buyers who wear the watch on a strap and care about how it sits under a shirt cuff, since case height is the first thing anyone notices.
Criterion 2: Dial, Hands, and Printing
Look at the applied numerals, the leaf shaped hands and the printed scale. Font weight, spacing and alignment matter more than any single feature. The running seconds and the chronograph minute counter must sit where the reference puts them, and the sub dial rings should be crisp rather than fuzzy. On a two register dial the sub dial positions are the fastest giveaway, because a movement not designed for that layout forces the maker to compromise the spacing. Check the hand length: hands that stop short of the minute track or overshoot it are a common fault.
Pros
- Dial photos at high magnification show print quality, alignment and sub dial position clearly.
- Good dial work carries most of the visual impression at normal viewing distance.
Cons
- Print and lume quality vary between batches from the same source.
- Colour shift between the genuine dial and a copy is hard to judge from seller photos.
Best for: anyone buying to wear daily, because the dial is what you actually look at.
Criterion 3: Movement and Chronograph Function
Three broad options exist. Quartz versions are thin, cheap and quiet but the chronograph sweep gives them away instantly. Automatic chronograph builds derived from the 7750 family are the common middle and upper tier, and they need a modified layout to place the sub dials correctly. Hand wound chronograph builds sit at the top of the replica market and feel closer to a mechanical original, at a higher price and with fewer service options.
Test the pushers in person or on video. A clean start, stop and reset with a snappy zero return is a good sign. A creeping chronograph hand, a sluggish reset or a rotor that rattles against the caseback is not.
Pros
- Automatic chronograph movements give a working chronograph and a sweeping seconds hand.
- Parts and service for common chronograph bases are widely available from independent watchmakers.
Cons
- Modified chronograph movements add thickness and reduce long term reliability.
- Quartz versions look right in photos and wrong on the wrist to anyone who knows the reference.
- Water resistance claims are rarely tested and should not be trusted near water.
Best for: buyers who will actually use the chronograph, which points to an automatic build rather than quartz.
Criterion 4: Crystal, Strap, and Clasp
The crystal on this reference family is domed and should show a clear, low distortion view of the dial with a coating that cuts glare without turning blue. On the strap, alligator grain and stitching quality decide whether the watch looks like a dress piece or a market stall find. Clasp engraving, spring bar fit and buckle finish are small details that buyers notice when they handle the watch.
Pros
- Sapphire crystal and a quality strap are inexpensive upgrades that transform the look.
- Strap swaps let you change the character of the watch without touching the case.
Cons
- Mineral glass scratches and looks dull under strong light.
- Supplied straps on budget copies often feel stiff and crack at the lug ends.
Best for: buyers who plan to swap in an aftermarket strap and want the case and dial to carry the look on their own.
Checks to Run Before You Pay
- Confirm the dial, metal and layout the IW371645 reference should have.
- Ask for caliper photos of diameter, thickness and lug width.
- Ask for a video showing the chronograph starting, stopping and resetting.
- Request macro shots of the dial print, sub dials and caseback engraving.
- Check the seller return window and whether the watch ships in a protective case.
- Budget for a strap upgrade and a service check by a local watchmaker.
Run those six checks and the choice usually narrows to one or two listings. Skip them and you are buying a photograph rather than a watch.