The chronograph is a relatively recent complication, first appearing in the 19th century. A chronograph watch features a mechanism for measuring and displaying an elapsed time period. The measurement is generally made in seconds, minutes and hours. The chronograph is often incorrectly referred to as a chronometer. In fact, the term 'chronometer' refers to a certification awarded to movements that have successfully passed a succession of quality and reliability tests organized by the COSC (Contrôle Officiel Suisse des Chronomètres [Official Swiss Chronometer Testing Institute]). There are different types of chronograph complications, including the flyback chronograph, which launches a new timer while the first is running at the push of a single button; and the double chronograph, where a second hand measures intermediate time periods and then instantly 'catches up' with the chronograph’s main hand. Among the numerous Jaeger-LeCoultre chronograph watches, the Jaeger-LeCoultre Polaris Chronograph WT watch features a 30-minute and 12-hour counter.