COSC Certification
laboratories that had been established independently of each other from the late 19th century onwards.The term chronometer is often wrongly applied to timekeeping instruments fitted with an additional mechanism that may be set in motion by pushbuttons to enable measurement of the duration of an event. Such an instrument is in fact a chronograph or chronoscope. It may of course be chronometer-certified, provided it meets the criteria set for the standard.A chronometer is a high-precision watch capable of displaying the seconds and housing a movement that has been tested over several days, in different positions and at different temperatures, by an official neutral body (COSC). Each chronometer is unique, identified by a number engraved on its movement and a certification number given by the COSC.The chronometer-certification can be delivered either to mechanical movements or quartz movements. Mechanical movements must satisfy seven extremely stringent criteria to earn the much sought-after distinction. Each movement is individually tested over a period of fifteen consecutive days and nights, in five different positions and at three different temperatures.Quartz movements must satisfy eight criteria. Each movement is individually tested over a period of eleven consecutive days and nights, in one position and at three different temperatures.For further information please consult the following website : www.cosc.ch