When Blancpain launched the Fifty Fathoms in 1953, it set the standard for the modern professional dive watch. Three years later, another dive watch – the Bathyscaphe – emerged from the Manufacture in Le Brassus, this time intended for the general public, hence the smaller size better suited to civilian use. Alongside the requisite characteristics of legibility, a robust movement and a unidirectional rotating bezel, Blancpain has introduced an annual calendar complication which tracks day, date and month with just one adjustment per year, at end February. Cased in steel, this Bathyscaphe annual calendar comes with a sail canvas or NATO strap, or metal bracelet.