Patek Philippe's "World Time" is a masterpiece that inherits the 24-hour display mechanism invented by watchmaker Louis Cottier, and the city ring on the bezel and the 24-hour ring work together to instantly know the current time in 24 cities around the world. The 5230/5231 series is equipped with an ultra-thin automatic Cal. 240 HU in a 38.5 mm case, and by simply switching the local city one step with the patented push button at the 10 o'clock position, the hour hand and 24-hour ring jump simultaneously to complete the operation. The cloisonné (wired enamel) map and guilloche engraved dial enhance its value as a work of art, and the movement thickness of only 3 mm also makes it comfortable to wear as a dress watch. This timepiece combines gorgeous decoration and practicality, and is extremely popular among business people and collectors who travel around the world.