Patek Philippe

Launched in 1968, the reference 3520D embodies Patek Philippe’s pursuit of elegance through technical refinement. At its introduction, the broader 3520 line had already been advertised as the flattest waterproof wristwatch in the world, first presented in 1965. The 3520D variant, distinguished by its hobnail “Clou de Paris” bezel—hence the “D” for décor—became one of the most recognisable expressions of the brand’s understated style.

The reference evolved through two movements: the calibre 175 (1965–1977), a Piguet-based movement beating at 18,000 oscillations per hour and stamped with the Geneva Seal, followed by the calibre 177 (1977–late 1980s), with 21,600 oscillations and famed as the thinnest in its category. Cases were crafted by Wenger for the smooth-bezel ref. 3520, and by Ateliers Réunis for the hobnail “D” versions, while dials were supplied by Stern Frères and later Stern Créations.

Produced in yellow, pink, and white gold, the reference 3520D remained in the Patek Philippe catalogue for an extraordinary four decades, finally discontinued in 2008. Today, it stands as a benchmark of timeless design and a milestone in ultra-thin waterproof wristwatches.