Portofino Chronograph Red Gold / Silver

In Context

At 42 mm it is sized to the current mainstream: 40 mm is the median across every watch measured in this catalogue. At 13.5 mm it is a tall case, and it will catch on a cuff. 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. 44 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.

3910 stands on its own in this catalogue — no other reference here shares its base number. It pairs a silver dial with a red gold case. Beyond the time it carries a chronograph.

The Portofino Chronograph's automatic chronograph, built on a Sellita SW500 — the clone IWC turned to once ETA stopped supplying Valjoux 7750 ébauches outside the Swatch Group. It is the direct successor to the 79320, which used the 7750 itself, and the layout carries over unchanged: counters at six, nine and twelve with a day-date aperture at three. IWC regulates and finishes the base before fitting it.

14 other watches in the library run the IWC 75320.

IWC

Portofino Chronograph Stainless Steel / Blue

IW3910-36 · 42 mm

IWC

Portofino Chronograph Stainless Steel / Black / Milanese

IW3910-33 · 42 mm

IWC

Portofino Chronograph Stainless Steel / Black

IW3910-08 · 42 mm

IWC

Portofino Chronograph Stainless Steel / Silver

IW3910-07 · 42 mm