When it comes to automatic watches, one brand is the Rolex. The company was the first to develop the perpetual movement in 1931. The perpetual movement is a self-winding mechanism in which a metal weight, or rotor, rotates in a fluid motion. The kinetic energy of the wearer is transferred to the mainspring by the rotor. It requires relatively little energy, and Rolex’s marketing department loves the name.
The Rolex name is synonymous with accuracy. A watch with a COSC chronometer certification is among the most accurate available. This certification is given to watches with movements that are within four to six seconds from a constant source in a 24-hour period. The COSC is an independent testing institute and Rolex is one of the few manufacturers to submit virtually every mechanical watch movement to this standard. The COSC certificate guarantees that the Chronometers in Rolex watches are accurate.
The power reserve of an automatic watch is its ability to run from a fully wound state. The value is measured in hours. The earliest automatic watch models from Rolex and Harwood ran for about twelve hours without winding, while the earliest Rolex automatic watches ran for 35 hours – more than enough time to keep the time even if the wearer removed it from his wrist. By comparison, an automatic watch can run for more than 50 hours if the wearer keeps it wound.
In the past, Rolex used 3rd-party movements. However, this has changed. The Rolex Cosmograph Daytona, for example, uses a Zenith El Primero caliber that is exceptionally accurate. These days, Rolex is producing its own calibers. However, it is still important to know that Rolex SA has changed its corporate name from Montres Rolex Watch Company.