Short answer

A replica IW329108 is worth buying only if it matches the genuine IWC Aquatimer Automatic 42 on case size, bezel action, dial printing, and movement type. Grade a copy on those four points before you look at the price. Most failures show up in the bezel detents, the date window, and the seconds hand sweep.

Build your reference sheet

Reference IW329108 sits in the IWC Aquatimer line, a stainless steel dive watch family with a 42 mm case. Open the official IWC listing for the reference and write down six numbers: case diameter, case thickness, lug width, dial color, date position, and crystal material. Add the strap type and the bezel style. That sheet is the only standard you compare a copy against. A seller description is not a standard.

Inspection steps

  1. Measure the case with digital calipers at the 2 and 8 o'clock points, then across the lugs.
  2. Turn the dive bezel through one full rotation and listen for consistent clicks.
  3. Line the bezel triangle up with the 12 o'clock index and check for drift.
  4. Examine the dial printing with a 10x loupe, checking index height and font weight.
  5. Compare the date font and the date window edge against a photo of the genuine watch.
  6. Charge the lume with a phone light for 30 seconds and compare the glow color.
  7. Screw the crown down and count the turns, then check for side-to-side play.
  8. Inspect the caseback engraving depth and the spacing between characters.
  9. Time the watch over 24 hours on a timegrapher or against a reference clock.
  10. Have a watchmaker pressure test that specific unit before it touches water.

What the movement tells you

Copies in this price class run a Seagull ST2130, a Miyota 9015, or a Seiko NH35. The first two beat at 28,800 vibrations per hour, which gives a smooth sweep. The NH35 runs at 21,600 and looks slower. A quartz tick, a stuttering seconds hand, or a rotor that rattles on the wrist are signs of a low-grade build. No seller is shipping a genuine IWC calibre inside a replica case, and any listing that claims otherwise is false.

Details that separate a good copy from a bad one

  • Bezel alignment at 12 o'clock, with no gap between the insert and the case.
  • Applied indices that sit level, with polished edges and no glue visible.
  • A date window cut clean, with the correct font and position.
  • Bracelet end links that sit flush against the lugs, with no rattle.
  • Sapphire crystal with an even anti-reflective coating, not a blue haze.
  • Case finishing that transitions between brushed and polished surfaces on a straight line.

Water resistance

Treat any replica as splash resistant until a watchmaker pressure tests that exact watch. Gasket quality and caseback sealing vary between units, even from the same seller. A rating printed on a caseback is a claim, not a test result. Do not dive or swim with a copy, and rinse it with fresh water after any contact with salt water.

Before you pay

Ask for photos of the actual watch, not catalog images. Request a short video of the seconds hand and of the bezel turning. Confirm the return window in writing and pay with a method that allows a chargeback. If the seller cannot show the watch running, walk away.