This Patek Philippe Perpetual Calendar reference 3448, known as the Disco Volante, was the firm's first self-winding perpetual calendar wristwatch. Its automatic caliber 27-460 Q pairs the perpetual calendar with a moonphase, a combination that gives the reference its place in Patek's modern history. The nickname comes from the broad, bezel-less case profile, and for a collector it remains one of the clearest expressions of mid-century Patek design. In 18k yellow gold the case measures 37.5mm across and 11.5mm thick, a proportion that still feels remarkably modern. The silver dial keeps the display restrained despite the complexity. More than a landmark complication, the 3448 marked the point where Patek joined everyday practicality to one of its most exacting complications, and that balance is why the reference still sits so high in the perpetual calendar line.