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IWC · Portofino

Strap for IWC Portofino IW4581-03

The Portofino Automatic 37 Stainless Steel / Diamond / Silver takes 18 mm straps. Verified lug width, the straps that fit this model, and answers to the most common questions.

Lug width

18mm
18 mm strapsAll IWC
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Lug width18 mm
Case diameter37 mm
ReferenceIW4581-03 (aka: 4581-03, IW458103)
FamilyPortofino
MovementIWC caliber 35111 Hours, Minutes, Seconds | Date
CaseStainless Steel

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

Standard spring bar · length 18 mm · Ø 1.8 mm double flange · industry standard, no brand part number

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Portofino Automatic 37 Stainless Steel / Diamond / Silver — watch

Straps for the Portofino IW4581-03

Selected for the 18 mm lug width

All 18 mm straps →

What I'm asked about the IWC Portofino IW4581-03

What strap size does the IWC Portofino IW4581-03 take?

The IWC Portofino IW4581-03 needs 18 mm between the lugs, usually 16 mm at the buckle. It's the size I've been fitting on it for years.

Can the strap on the IWC Portofino IW4581-03 be changed?

Yes. It has spring bars between the lugs: with the right tool the strap comes off in a minute. If you'd rather not risk a scratch, I do it in the workshop.

Can I put a leather strap on the IWC Portofino IW4581-03?

Yes, in 18 mm leather. On a 37 mm dress watch alligator is the natural choice: thin, elegant, what it was born for.

Which strap do you recommend for the IWC Portofino IW4581-03?

A thin 18 mm alligator. You'll find it ready in the 18 mm collection. If you'd rather have something built on your wrist, the Casati atelier.

For changing the strap

Classic Strap and Bracelet Removal Tooltwo-tip spring bar tool→Milano Straps Premium Swiss Standard Watch Bucklestang buckle, steel or PVD→Leather Conditioner Milano Strapsnourishes and protects the strap→Casati Milano Rectangular Epsom Leather Travel Case — Brownfor the watch and spare straps→

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

Request an appointment →

Casati Milano · Via XX Settembre 15, Milan · by appointment only

Bespoke straps for IWC, in the atelier or by video call: casatimilano.com