Reference 3504 is a waterproof model - with screw back case - featuring center seconds and exquisitely 1960s design. It is defined by the faceted lugs, following the trend of the time which was imposing more and more elaborate case shape alongside with more and more clean dial designs. The cases were realized by Geneva-based master case maker Antoine Gerlach, identified by the hallmark to the inside of the back: a 4 within key. Obviously, such a case construction is extremely sensitive to polishing and often what is left of such faceted lugs is only a pale shadow of their former glory. Fortunately, in this instance the case was only gently cared for through the years, without aggressive interventions, and the lugs still display well defined their facets.

Reference 3504 is a very obscure reference; it is not uncommon, even for enthusiasts of the vintage Patek Philippe production, to not even know this reference exists. That is because it is one of the most elusive Patek Philippe models, produced for one year only, an extremely unusual occurrence, between 1963 and 1964. Furthermore, it would appear that the model was cased exclusively in white gold, another extremely unusual trait. A direct consequence of such a short production run is its absurd rarity: before the discovery of this previously unknown example, only 2 other specimens of this reference were known by the market. This is a truly uncommon occasion for the shrewd collector to own a Patek Philippe wristwatch which is more rare than grail pieces such as the steel 1518, and at a very different price point.