What is a COSC-certified quartz chronometer?
A chronometer is a watch that has obtained an official rate certificate from the COSC (Contrôle Officiel Suisse des Chronomètres), after having passed the precision tests in different positions and at different temperatures over a 15-day period. Thermocompensated means that the effective temperature in the watch is measured and taken in-to account when improving precision. This eliminates the known problem that the accuracy of a normal quartz watch may deviate by several seconds per week due to changes in temperature. This is the only way that a quartz movement can meet the extremely high demands placed on it by COSC. Precision is 20 times more accurate than on a normal quartz watch, i.e. +/- 10 seconds per year (0.07 seconds/day).
