A crown that aids water resistance by sealing the crown to the case of the watch. The seal is achieved by the matching of a threaded pipe on the case with the crown's internal threads and gaskets, while twisting the crown to lock it into place.
Self-Winding
This term refers to a mechanically powered watch that is wound by the motion of the wearer's arm rather than through turning the winding stem (manual mechanical). In response to this motion, a rotor turns and winds the watch's mainspring. Most automatic watches have up to 36 hours of power reserve. If an automatic watch is not worn for a day or two, it will wind down and need to be wound by hand to get it started again.
Shock Resistance
As defined by the U.S. government regulation, a watch's ability to withstand an impact equal to that of being dropped onto a wood floor from a height of three feet.
Stainless Steel
An extremely durable metal alloy (chromium is a main ingredient) that is virtually immune to rust, discoloration, and corrosion; it can be highly polished, thus resembling a precious metal. Stainless steel is often used even on case backs on watches made of other metals and is the metal of choice used to make high quality watchcases and bracelets. It is also hypoallergenic because it doesn't contain nickel.
Subdial
A small dial used for any of several purposes, such as keeping track of elapsed minutes or hours on a chronograph or indicating the date.
Titanium
A "space age" metal, often having a silver-gray appearance. Because it is 30 percent stronger and nearly 50 percent lighter than steel, it has been increasingly used in watch making, especially sport watch styles. Its resistance to salt water corrosion makes it particularly useful in diver's watches. Since it can be scratched easily, some manufacturers use a patented-coating to resist scratching. Titanium is also hypoallergenic.
Unidirectional Rotating Bezel
An elapsed time rotating bezel, often found on divers watches, that moves only in a counterclockwise direction. It is designed to prevent a diver who has unwittingly knocked the bezel off its original position from overestimating his remaining air supply. Because the bezel only moves in one direction, the diver can err only on the side of safety when timing his dive. Many are ratcheted, so that they lock into place for greater safety.
Water Resistance
Describes the level of protection a watch has from water damage. See the "water resistance" section for a description of the different levels.
Most Commonly Used Watch Terms
