Short answer
A fake IW329135 is any watch built to imitate IWC's Aquatimer Automatic in the IW3291xx reference family. That label covers a wide spread of products: a cheap quartz mall copy, a mid-tier automatic with a decorated generic movement, and a premium 1:1 replica that matches case dimensions, dial printing, and hand geometry. The three fastest tells are movement type, case finishing, and dial text. Price tracks those three, so a watch priced far below the rest of the market is not a hidden bargain.
What the genuine reference establishes
IW3291xx models are built around a stainless steel case of roughly 42 mm, an internal rotating dive bezel, a screw-down crown, and a self-winding movement. Those are the parts a copy has to reproduce, and every one of them is measurable. Case diameter, lug width, thickness, and crown thread pitch do not vary between a good copy and a bad one when the maker worked from the real watch. When numbers drift from published specifications, you are looking at a generic case rather than a faithful replica.
Three tiers to expect
- Tier 1: quartz movement, stamped dial, mineral glass, plated case, painted bezel markings.
- Tier 2: automatic movement, sapphire crystal, steel case, printed dial, but soft crown action and shallow engraving.
- Tier 3: 1:1 replica with matching dimensions, correct dial font and spacing, working internal bezel, and a movement that winds smoothly in both directions.
How to inspect one, step by step
- Measure the case across the crown guards with digital calipers and compare the reading to the published diameter.
- Weigh the watch head on a kitchen scale and compare it to the figure you expect for a steel case of that size.
- Rotate the internal bezel through a full turn and check that it clicks at each marker instead of sliding.
- Unscrew the crown and count the turns; a correct thread runs several turns and stops cleanly.
- Look at the dial text under a loupe and check the letter spacing, stroke weight, and alignment of the brand line.
- Flip the watch over and read the caseback engraving; shallow, blurry, or off-center text points to a low-grade copy.
- Angle the crystal toward a light source and confirm there is no purple or blue tint from a coated mineral glass.
- Hold the watch to your ear and listen; a fast ticking beat indicates quartz, not the automatic movement you were promised.
Movement and water resistance
Movement is the single largest cost driver in any replica. A true 1:1 build uses an automatic caliber with a sweeping seconds hand at roughly 28,800 vibrations per hour. Water resistance is a separate question. ISO 6425 defines the tests a diver's watch must pass, including pressure testing and condensation checks, and no replica should be trusted near water without its own test result. Treat any depth claim on a copy as unverified until a watchmaker pressure-tests the case.
Questions to ask before you buy
- Ask which movement is installed and at what beat rate.
- Ask for the measured case diameter, thickness, and lug width.
- Ask whether the internal bezel is functional or fixed.
- Ask about crystal material and any anti-reflective coating.
- Ask for real photographs of the exact unit, not catalog images.
Where the tells always surface
Finishing quality is hardest to fake. Brush and polish transitions on a genuine case are sharp and defined, while copies round them off during buffing. Crown action is the second consistent giveaway, because thread cutting is expensive. Dial printing is the third. If those three details hold up under magnification, the rest of the watch usually follows.