IWC IWC - IW4581-10 Portofino Automatic 37 Stainless Steel / Ardoise / Milanese

Portofino Automatic 37 Stainless Steel / Ardoise / Milanese

REF. IW458110

5/10

Scarce

Case

MaterialStainless Steel

Diameter37 mm

ShapeRound

CrystalSapphire

Case backClosed

Water resistance30 m

Dial

ColourGrey

Finishon the dials reflects light in a myriad of different ways, while the polished surfaces of the case, like the guilloche work, give the watches an opulent style of their own. Alligator leather straps from Santoni in delicate nuances of colour, from light and dark brown to grey and black, as well as in orange, lilac and red, complement the dial and case of nine of the models perfectly, while one of the stainless-steel models is fitted with an exquisite Milanaise mesh bracelet. Each timepiece is also available with a Milanaise mesh bracelet in stainless steel or 18-carat red gold. Reference: IW458110

IndexesGem-Set Indexes Hands: Feuille

HandsFeuille

Movement

Caliber35111

Typeautomatic

Reserve42 h

Explore caliber→

In Context

At 37 mm it sits just under the modern norm — the band that suits the widest spread of wrists. At 9 mm thick it is about average for a modern wristwatch. The case back is closed, so the movement stays out of sight, and the sapphire crystal will resist everything short of deliberate abuse. Rated to 30 m, it is protected against rain and splashes and nothing beyond that.

The movement winds itself from the motion of your wrist. 42 hours of reserve carries it overnight, but not through a weekend in a drawer. At 28,800 vph the seconds hand advances 8 times a second.

IW458110 stands on its own in this catalogue — no other reference here shares its base number. It pairs a grey dial with a stainless steel case.

Inside: Caliber 35111

Explore this caliber →

The 35111 is IWC's version of the Sellita SW300-1, built by Sellita to IWC's specification and the successor to the ETA-based 30110. It powers 70 watches in this library. The SW300 is Sellita's equivalent of the ETA 2892-A2, produced after ETA restricted supply to outside brands, and it matches the 2892's dimensions: 25.6 mm across and thin enough for a dress case. IWC's version runs at 28,800 vph with a 42-hour reserve and 25 jewels, carries a date, and is finished and regulated by IWC. The [2892 piece](/blog/the-eta-2892) explains the architecture both movements share. In the library it sits under 38 [Portofino](/brands/iwc/portofino) references, the Automatic 40 and Automatic 37, 20 [Pilot's Watches](/brands/iwc/pilot), the Mark XVIII of 2016 in its 40 mm case, 9 [Da Vinci](/brands/iwc/da-vinci) Automatic 36s of 2017 and 3 [Ingenieurs](/brands/iwc/ingenieur). The 40 mm case accounts for 37 references, the 37 mm for 16 and the 36 mm for 14. Seven are limited editions. The [30110](/calibers/iwc-30110) is the ETA-based movement it replaced, and the [32111](/calibers/iwc-32111) the in-house five-day movement that replaced it in turn.

69 other watches in the library run the IWC 35111.