Patek Philippe, Super Complex function timepiece, model: 5035J-001, automatic mechanical movement, 18K gold, Watch diameter: 37mm. It is the first mass-produced annual calendar wristwatch of Patek Philippe and even the entire watchmaking industry. Its annual calendar system can automatically identify large and small months. It only requires manual adjustment once a year in February, which is much more convenient than ordinary calendar watches. At the same time, its price is much lower than that of perpetual calendar watches, making it the "king of cost performance" among complex functions.