This vintage Audemars Piguet Perpetual Calendar ref. 25548BA is an exceptional example of Swiss haute horlogerie, produced in 1985 and crafted in solid 18kt yellow gold. Featuring a 36 mm case with elegant proportions, it showcases a refined champagne dial with applied gold hour markers and four perfectly balanced subdials displaying the perpetual calendar functions: day, date, month, leap year, and moon phase. Powered by the legendary ultra-thin automatic Audemars Piguet Caliber 2120/2800, based on the Jaeger-LeCoultre 920, this movement is celebrated for its precision and technical excellence. Freshly serviced and offered with its original box and instruction booklet, this reference is a highly collectible and historically significant timepiece, combining timeless design with one of the finest perpetual calendar movements ever produced.