In 1996 Patek Philippe were awarded a swiss patent for a new type of calendar indication, the “Annual Calendar”. This new complication indicates 30 and 31 of each month and only has to be reset on the 28th or 29th of February each year. The first wrist watch to carry this new mechanism was the ref 5035 “Annual calendar”. Now discontinued, this new model paved the way for many future models and a Patek Philippe design that has grown in to one of the companies most iconic designs. Descendant of the original, this particular model of annual calendar is the very fine and rare Patek Philippe ref: 5146. Made in an all 18ct rose gold round case with stepped bezel and held on a genuine brown alligator strap with matching 18ct rose gold folding clasp. Fitted with the highly complicated and decorated Manufacture caliber 324 S IRM QA LU mechanical self-winding movement. Features include annual calendar day, date, month, moonphase and power reserve. Cream dial with applied gold numerals and markers. Finished with a sapphire crystal glass and case back.