Short answer

IW938907 does not appear in IWC's catalog. The brand's references follow an IW plus six-digit pattern, and the 93xxxx block does not line up with any documented IWC series. What you are looking at is a seller's stock code, a number invented to group one dial and case combination under a single listing. Treat it as a SKU, not as a model identity.

That distinction matters. A code on its own tells you nothing about what the watch is trying to imitate. If the only thing in a listing is IW938907 and a price, you do not yet know whether you are looking at a Portugieser-style dress watch, a Pilot's-style flieger, or a generic round case with a printed logo and a date window.

Why sellers use codes like this

Replica listings get copied, mirrored, and reposted across storefronts. An internal code lets a seller track the same photo set across several shops without naming the brand. It also makes comparison shopping harder, because you cannot search for a genuine equivalent and pull up side-by-side specs. Some sellers recycle one code across two or three different watches as they change suppliers.

So the first job is to make the code useless as a shortcut. Ask directly what case size, dial color, and movement the listing covers. If the answer is vague, that is your answer.

What to pull out of a listing

• Case diameter and lug width in millimeters, not "large" or "classic size"
• Dial color, layout, and whether subdials are functional or decorative
• Movement type and caliber name, if the seller will state one
• Case material, plus whether the back is a display case or solid
• Strap or bracelet specs, including clasp type

What separates a solid replica from a bad one

Price bands are not reliable. Construction is. I look at four things in this order: the case, the dial printing, the crystal, and the movement.

• Case. Look for crisp lug edges, even brushing, and a bezel that lines up flush with the midcase. Polished surfaces that look hazy usually mean a cheap alloy rather than stainless steel.
• Dial. Printed text should be sharp under magnification. Blurry logos, thick date fonts, and misaligned markers are the giveaway on budget builds.
• Crystal. Sapphire with anti-reflective coating is standard on mid-tier and up. Mineral glass scratches and shows more glare.
• Movement. This drives most of the cost and all of the service life.

Movement tiers, roughly

• Quartz: accurate, cheap, no service need, wrong sweep on the seconds hand
• Asian automatic (Miyota, Seiko NH-series, Chinese equivalents): reliable, serviceable, modest beat rate
• ETA-clone automatics (2824, 2892, 7750 patterns): smoother sweep, parts exist, watches run in the low hundreds
• Decorated or "super clone" movements: closest visual match to the original, hardest to service, most expensive

Be skeptical of a "Swiss made" stamp on a watch that costs less than a decent pair of shoes. The marking costs nothing to apply.

Water resistance claims

A rating printed on a listing is a claim, not a test result. Gaskets on replicas are the first thing to fail, and most are assembled without pressure testing. I would not swim in one regardless of what the description says. If you get caught in the rain, fine. If you dive, wear something else.

The legal side in the US

Importing merchandise that infringes a US trademark is prohibited, and Customs can seize a shipment. Selling a replica while presenting it as genuine is fraud, and that line is what separates a gray-market purchase from a criminal one. Reselling on a marketplace under a real brand name is the version of this that gets people into trouble. Keep it for yourself, be honest if you ever pass it on, and do not expect a manufacturer to service it.

Bottom line

IW938907 is an inventory label, so ignore it and evaluate the watch. Get the case size and movement in writing, look at real photos of the exact unit, and assume water resistance claims are marketing. That approach works whether the code on the listing is IW938907 or anything else a seller makes up next week.