Legendary original military issued Blancpain Fifty Fathoms , the world's first purpose-built diving watch developed for French Navy combat swimmers. This historic timepiece features a robust stainless steel case measuring 41.5mm x 52mm, designed to withstand extreme underwater conditions. Equipped with the revolutionary rotating bezel, automatic movement, and exceptional water resistance to 300 feet. Produced from 1953 through the 1970s, this watch pioneered modern dive watch design and was adopted by military forces worldwide. An authentic piece of horological history representing the birth of professional diving timepieces and military innovation in underwater exploration