The Superlative Chronometer status is symbolized by the green seal that comes with every Rolex watch and is coupled with an international five-year guarantee.

The notion of Superlative Chronometer, first formulated in the late 1950s, forms a centrepiece on the dials of all Oysters. The rate results achieved showed greater precision than the criteria for obtaining a mention. To mark these exceptional qualities, Rolex created the term of “Superlative Chronometer”. This precision is tested by Rolex using an exclusive methodology that simulates the conditions in which a watch is actually worn and is much more representative of real-life experience.

Each movement is submitted to COSC (the Swiss Official Chronometer Testing Institute) for its official certification, after 15 days and 15 nights of testing involving seven eliminating criteria in five static positions and at three temperatures. In 1914, a similar Rolex wristwatch was granted the first “Class A” precision certificate by the famous Kew Observatory in Great Britain, the highest authority in the world in terms of precision, and responsible for the certification of marine chronometers.

Rolex’s Superlative Chronometer certification reflects the pursuit of its goal by adopting the strictest chronometric precision criteria in the industry, criteria which are more representative of real-life wear. The brand can therefore offer its customers a superlative level of performance that pushes back the limits of mechanical watches and makes Rolex the benchmark of watchmaking excellence.

肩负着历史悠久的精准使命，劳力士手表的绿色印章吊牌代表着顶级天文台精准时计至高无上的象征，并且享有 5 年的国际保修福利。

二十世纪五十年代末，劳力士构想出超卓天文台精密时计概念，所有蚝式腕表的表盘中央均印有此标志。而获得的测试结果是比标准更为严格苛刻。为了表扬卓越的精确品质，劳力士创造了”超卓天文台精密时计”的术语。劳力士研发出非凡卓著的检测方式及高科技设备为腕表进行测试，并授予其“超卓天文台精密时计”的认证。

每枚机芯均送往瑞士官方天文台认证 (COSC) ，历经十五个昼夜的测试后，方能获取其官方认证。其中包含七项淘汰基准，并在五个静态位置及三种温度状况中进行测试。所有劳力士机芯均获授予此瑞士天文台精密时计认证。1914年，一款相近的劳力士腕表亦获著名的英国乔城天文台 (Kew Observatory) 颁授“A级”精密时计认证，乔城天文台是世界上评定精准度的最高权威，负责颁发航海天文钟的认证。

劳力士超卓天文台精密时计认证采用钟表业中最为严格的计时精密基准。此基准不仅更贴近日常生活的佩戴情况，并展现品牌力求精准的决心。由此，劳力士便能为顾客提供超卓性能的腕表，不断突破机械腕表极限，成为超卓机械腕表制造商的典范。