Certina diver DS-2 Super PH 1000M

The first diver’s models came on the market around 1960, shortly after the introduction of the DS product line (1959).

DS referred to double security. The movement was to be secured against water and shock resistance through both a rubber insulating cushion and the behemouth 44mm case you see here.

This PH1000M was used in the Tektite II continuation experiment and performed admirably. I highly recommend reading further here, as the modules, living conditions, experiments, and outcomes are all fascinating.

This Certina diver watch 100 atm is in outstanding conditions. The warm dark pumpkin patina is breathtaking, which is not the best thing if you're doing an immersion. Case is pristine, unpolished, and shows well the different matt/shining textures. The bakelite black bezel is in perfect conditions.
The watch comes with its original Gay Frères bracelet.