Top pick: a mid-tier replica of the IWC Portugieser Chronograph reference IW371647 running a 7750-derived automatic chronograph, with a 41 mm case, subdials placed at 12 and 6, and a dial that copies the feuille hands, applied numerals, and printed minute track of the original. It wins because this reference is judged on proportion and dial layout, not on box contents. The criteria behind that call: case diameter and thickness, subdial position and spacing, hand shape and finish, crystal coating, movement type, strap width, and how plainly the seller describes water resistance.

What the IW371647 reference is

IW371647 sits in the 41 mm Portugieser Chronograph family, the two-register line that carries running seconds at 6 and a chronograph minutes counter at 12. The design cues are a slim polished bezel, a wide dial, leaf shaped hands, applied Arabic numerals, and a thin printed track around the outer edge. Current production uses an in-house column wheel chronograph, which is exactly what no replica at a normal price can copy. That gap is the most useful thing to know before you shop.

The caseback is transparent on this reference, so the movement stays visible. A replica cannot hide behind a solid back, which makes rotor finishing, bridge shapes, and screw color part of the purchase rather than a footnote.

The criteria that decide a purchase

  • Case width and thickness: 41 mm across is easy to fake, a slim profile is not.
  • Subdial placement: counters must sit on the vertical axis at 12 and 6, not drift toward the center.
  • Dial furniture: hand shape, numeral font, and the length of the printed track.
  • Crystal: single or double anti-reflective coating changes how the dial reads in daylight.
  • Movement: automatic chronograph versus quartz, and what shows through the caseback.
  • Strap or bracelet fit: lug width and end link gaps.
  • Disclosure: sellers who state limits on water resistance and service are easier to deal with.

Option 1: 7750-derived automatic build

The most common approach, and the one to pick if you want a winding rotor and a sweeping chronograph hand.

Pros

  • Automatic winding matches the feel of the original.
  • Subdials can be arranged at 12 and 6, which is the correct reading for this reference.
  • Serviceable by independent watchmakers in most US cities.
  • The caseback has something to show.

Cons

  • Thicker than the genuine 41 mm case, so it sits higher on the wrist.
  • Pusher feel is heavier and reset can be less crisp.
  • Costs more to buy and more to repair.

Use case: daily wear for someone who takes the watch off before swimming, shows the caseback, and wants the chronograph to work as a chronograph.

Option 2: quartz chronograph build

The thin, cheap, and consistent path.

Pros

  • Case can be made closer to genuine thickness.
  • Accurate timekeeping with no service interval.
  • Lower entry cost, so a damaged watch hurts less.

Cons

  • A ticking small seconds hand at 6 gives the game away to anyone who knows the reference.
  • Caseback is often wrong or blank.
  • Lighter feel, and the rotor-shaped weight on some movements is cosmetic.

Use case: occasional wear, a display piece on a shelf, or a first purchase while you decide whether the reference suits your wrist.

Option 3: decorated display-back build

A variant of the automatic option with extra work on the visible movement: engraved bridges, blued screws, and a signed rotor.

Pros

  • Caseback photos hold up to a closer look.
  • Often paired with sapphire on both sides.

Cons

  • Decoration is cosmetic and does not improve timekeeping.
  • Higher price for a detail only you will see.
  • Fragile finishing can flake if the watch is opened by an unskilled hand.

Use case: collectors who already own a daily watch and want the display back to be the point of the piece.

Checks before you pay

  1. Ask for a straight-on dial photo and a profile photo next to a caliper.
  2. Confirm subdial positions and that the chronograph starts, stops, and resets.
  3. Ask the lug width, then confirm the strap you want will fit.
  4. Request an honest water resistance statement. Assume none unless stated.
  5. Confirm what happens if the watch arrives with a movement fault.

Legal and shipping reality in the United States

Counterfeit watches are subject to seizure at the border, and importation carries risk that lands on the buyer. Treat delivery as uncertain, keep records, and do not assume a package that clears once will clear again. Nothing in the buying process changes the fact that the watch is a copy.

Short answer

For the IW371647, the automatic 7750-derived build with correct 12 and 6 subdials is the pick most buyers should make. Quartz makes sense only when thickness and budget matter more than the seconds hand, and the decorated display-back version is for people who already have the basics covered. Verify proportions first, movement second, and everything else third.