For sale is a Zenith S.58 Mark II automatic diver from 1959.

Unknown service history

Price Euro 3700



Info from Rescapement´s excellent guide to S.58
While early advertisements clearly touted the brand’s caliber 120, within the late 50s dive watch market, Zenith needed to develop and update the S.58 to an automatic movement. Little time was wasted; just two years after the initial release Zenith completely reworked the midcase and caseback allowing room for the caliber 133.8 bumper automatic.

This Mark II case comes in a millimeter thicker than the first S.58 at 8.6mm compared to 7.6mm, thickness measured without the crystal from the highest point of the bezel. This one millimeter change has a fairly significant impact on wrist feel as the caseback is no longer completely flat but, rather, stepped.

Aside from wrist feel, viewing the two straight on, you would never notice a difference aside from the script automatic text. Zenith beefed up the model but did not change the case from a two-dimensional point of view: both Mark I and Mark II measure 36.6mm in diameter and 45.5mm lug-to-lug.

Right around 77,000 cal. 133.8s were manufactured by Zenith, with a very small amount of those being cased in S.58s — the observed case number range for Mark II examples is 9.48 millions to 9.65 million.