If you want one answer: the replica IW371651 worth buying is the 41mm Portugieser Chronograph copy that runs an automatic 7750 based chronograph movement, keeps the case near 13mm thick, and places the small running seconds at 6 o'clock with the 30 minute counter at 12. Everything else, the dial print, the leaf hands, the strap, the clasp, matters, but those four points decide whether the watch looks right on the wrist and feels right in the hand. The checklist below follows the order in which flaws become visible to other people.
What the IW371651 Is on the Real Watch
IW371651 sits inside the Portugieser Chronograph 41 series, the reference family that replaced the older 3714 generation. The genuine watch measures about 41mm across, runs the in-house calibre 69355, and shows a clean bi-compax dial with small seconds at 6 o'clock and a 30 minute chronograph counter at 12. There is no date window. The hands are leaf shaped, the numerals are applied, and the crystal is domed sapphire.
Because the 3716 series covers several dial colours and strap combinations, confirm which dial and strap the reference you are ordering actually maps to before you pay. A seller who cannot tell you the dial colour tied to that number is guessing, and guessing sellers rarely ship the unit in the photos.
Dial and Hands: The First Place a Copy Shows
- Pros of a strong dial: applied numerals with thin, polished edges, a crisp printed minute track, recessed subdials with a subtle snailed texture, and leaf hands with the correct curve.
- Cons to watch for: painted numerals that sit flat on the surface, subdials spaced too far from the centre, and a chronograph seconds hand that does not return to 12 when you reset.
Run the chronograph for two minutes, reset it, and repeat three times. A hand that stops a hair short of 12 or a hair past it tells you more about the movement than any spec sheet will.
Case, Crystal and Thickness
- Pros: a case close to 41mm across with thickness near 13mm, lugs that curve toward the wrist, and a domed crystal that catches light along the edge.
- Cons: a case that is 1mm or 2mm too thick, which lifts the watch off the wrist and changes the silhouette, plus flat crystals that look like a window instead of a lens.
Ask for caliper photos of the case sides, not just the front. Thickness is the measurement most often fudged, and it is the one you cannot fix after delivery.
Movement Tiers and What Each One Gives You
- Quartz: the cheapest path. The dial layout can still be correct, but the chronograph seconds hand ticks instead of sweeping. Skip it if you care about the second hand.
- Automatic 7750 based: the realistic option. Subdial positions can be built correctly, the pushers have a firm click, and the rotor winds as it should. It is also louder and thicker than an in-house movement.
- Decorated automatic: the same base with cosmetic finishing. Worth the premium only if you plan to show the caseback to someone.
Ask whether the movement is automatic or quartz before anything else. That single answer changes the price band, the weight, and the sound of the watch on the desk.
Strap, Clasp and Finishing
- Pros of a good build: a leather strap that breaks in within a week, a deployant clasp that lines up with the case, and brushing that matches across the lugs and buckle.
- Cons: stiff straps with sealed plastic edges, stamped clasps with sharp corners, and polished lugs on a brushed case.
Budget for a replacement strap. It is the cheapest upgrade available and the one that improves the watch most.
Pre-Purchase QC Checklist
- Caliper photos of diameter and thickness.
- Dial shots straight on, plus close ups of both subdials and the printed track.
- Chronograph start, stop and reset, filmed.
- Timegrapher reading if the seller has one.
- Lume shot taken in a dark room.
- Strap and clasp photographed from both sides.
Red Flags
- A date window anywhere on the dial.
- Subdials that are not at 12 and 6.
- Sellers who will not photograph the actual unit they are shipping.
- Sapphire claims with no edge shot or reflection test.
Who Should Buy Which Version
Buy the automatic 7750 based build if you wear the watch weekly and want the chronograph to work like a chronograph. Buy the decorated version only if the caseback matters to you. Avoid quartz entirely on this reference, because the ticking seconds hand is the fastest tell on a dial that is otherwise quite forgiving. Keep in mind that any copy is a copy: it carries no manufacturer warranty or service support, and some watchmakers will decline to work on a clone movement. Buy on that basis and you will not be disappointed.