Water-resistant wristwatch 防水腕表
The case, winding-crown, push-pieces and crystal are so constructed as to be able to resist penetration by dust or water. A pressure of 3 atmospheres is equivalent to a pressure of 3 kg/cm² and corresponds to the pressure experienced by a watch submerged to a depth of 30 meters below the water’s surface. A water-resistant wristwatch (étanche) should be rechecked and serviced annually to preserve its impermeability to water.
表壳、表冠、按钮和水晶表镜的结构都必须足以防上液体或灰尘入侵。3大气压相当于3 kg/cm²的压力，也就是30米深度。防水腕表 (étanche) 应每年检查和保养一次，以确保其防水性能。
World time indication (UTC, GMT) 世界时间显示 (UTC, GMT)
As one travels eastwards or westwards from zero degrees longitude (the Greenwich or “prime” meridian), one’s local time deviates from GMT by one full hour for every 15º traversed. This world time system was first introduced by Canada and the USA in 1883. The dials of watches with World time indication display the time in two or more time zones. To accomplish this, it is necessary either to put several watch-movements inside a single case or else to add an additional mechanism. (A so-called “heure universelle” can simultaneously show as many as 24 different times.) World time wristwatches were first made in the 1930s. They are particularly popular with long-haul pilots, as well as with businesspeople who frequently make long-distance telephone calls from one time zone to another.
如果从0经度（格林威治或主子午线）向东或西走，每经过15度，时间就会与GMT相差1小时。加拿大和美国率先于1883年引进世界时间。具世界时间功能的表款可同时显示两个或更多时区的时间。因此必须在单一表壳内装置多个机芯或添加额外机件（名为heure universelle的装置可同时显示多达24种时间）。世界时间腕表于1930年代面世，受长途飞行员和商务人士钟爱。