Manual vs. Automatic

• Automatic mechanical wristwatches keep time to an acceptable level of accuracy without the need for daily adjustments. This advantage is lessened if the owner doesn't wear the watch often enough, which causes the automatic mechanism to stop. Manual mechanical wristwatches require periodic rewinding, usually once a day. There are no real performances advantages in either mechanism. An automatic is simply more convenient for most people.
  
  

Operation

• Automatic mechanical wristwatches convert kinetic energy generated by unpredictable movements of the wearer's arm into potential energy that winds the watch's mainspring. Usually, this transformation of energy takes place when an asymmetrically weighted half-disc of metal placed near the edge of the wristwatch rotates as a result of normal day-to-day human motor movements.
  
  

Chronograph

• The term "chronograph," which is often confused with "chronometer," refers to a watch that measures time in short-to-medium durations, in addition to the ordinary time-of-day measuring functions. Chronographs usually exist in subdials, marked with scales used to measure events other than elapsed time, such as a pulse rate.
  
  

Chronometer

• A chronometer is any watch that has passed the stringent accuracy tests issued by the Contrôle Officiel Suisse des Chronometres (COSC). The window of acceptable error to pass these tests usually falls between four to six seconds per day. A common concern regarding the relevance of COSC testing is that tests are not performed on watches, because they are sold in shops, and there is no way of knowing how a watch was treated between the time it was tested and when it reached a shop to be sold.
  
  

History

• The Caliber 11 was the first automatic chronograph and was developed by the group of Hamilton/Breitling/Heuer/Dubois Depraz. It was first exhibited at the 1969 Basel Fair alongside the efforts of rival mechanical watch design group of Movado/Zenith.