Certina introduced its DS system – “Double Security” – in 1959. The construction combined a movement suspended within an elastic shock-absorbing ring with reinforced Plexiglas, additional seals and a strengthened case back. The result was an exceptionally robust watch for its time, designed to withstand drops of up to six metres and water pressure equivalent to a depth of 200 metres.

This watch belongs to the earliest generation and is marked “Patent Pending” inside the case back, a designation used before patent number 346825 was introduced and before Certina adopted its well-known turtle emblem. The HF signature identifies the case manufacturer Huguenin Frères, which filed the patent application for the shock-resistant construction.

The watch is further distinguished by its “pie-pan” dial with crosshair decoration, one of the more distinctive dial variants associated with the first-generation reference 5601.012. Together with its dauphine hands and calibre 25-45, these details give the watch its characteristic early DS appearance.