A chronograph is a stop-watch for measuring a time interval. It has start/stop/reset functions activated by pushers, usually on the right case flank. A typical Oris chronograph can measure time intervals to 1/5th of a second. As well as the stop-watch functions, a chronograph also indicates the time through its hour, minutes and seconds hands. A chronometer is a watch with a movement accurate to within -4/+6 seconds a day, as certified by an official independent Swiss body called the Contrôle Officiel Suisse des Chronomètres, or COSC. A COSC chronometer certificate guarantees a watch’s movement has been tested for accuracy at various temperatures and in a variety of positions.