Anatomy of a Watch
A watchband or bracelet is a strap, band or bracelet of ceramic, cloth, leather, metal, plastic or rubber that attaches to the watchcase and wraps around the wrist to hold a wristwatch in place.
The ring that surrounds the watch face and holds the crystal in place. A sports or divers watch could have a rotating bezel to be used as a timer.
Attached to the watchband, a watchcase houses the bezel and dial, the movement (or the complete inner workings of a watch that keep the time, move the watch's hands, etc.) and the back, which is either snapped on or screwed in.
Case width is the approximate measurement, in millimeters (mm), from the edge of the bezel, diagonally across the watch dial to the other side.
Band length is the length of a watch from end to end. Men's watches are typically sized to fit wrists from 7 to 10 inches. Women's watches are typically sized to fit wrists from 6 to 8 inches. Adding or removing links can resize some watchbands or bracelets. Other bands offer several buckle holes for the best fit.
A rotating bezel is a bezel that can be turned. Different types of rotating bezels perform different timekeeping and mathematical functions.
Uni-Directional Bezel: A uni-directional rotating bezel moves only in a counterclockwise direction. Often found on divers' watches, the bezel can be used to measure elapsed time.
Bi-Directional Bezel: A bi-directional rotating bezel can be rotated either clockwise or counterclockwise. These bezels are often used for mathematical calculations such as average speed or distance.
Case length is the approximate measurement, in inches, of the watchcase between the points where it attaches to the watchband.
Case thickness is the approximate measurement, in inches, of the watchcase depth from the back to the front.