A tri-compaxTri-Compax A tri-compax watch is a type of chronograph watch that has three sub-dials ('triple register'), one for the chronograph minutes, another for the chronograph hours, and a third one for the running seconds [Learn More] watch is a type of chronographChronograph A chronograph complication is a feature in a watch that allows the wearer to measure elapsed time in addition to telling the time. It works by having a separate set of gears and levers, called the chronograph mechanism, which is activated by pressing a button or a pusher. The chronograph mechanism starts and stops the chronograph's second hand, which is usually located on the watch's dial, separate from the regular watch hands. The elapsed time is usually displayed on a sub-dial or a register on the watch's dial. [Learn More] watch that has three sub-dials (‘triple register’), one for the chronograph minutes, another for the chronograph hours, and a third one for the running seconds