(I) A wristwatch is a mechanical device which is used for telling time. (II) Its main advantage over other types of time-telling devices (such things as clocks, sundials, or hourglasses) is that it is small enough to be worn on the wrist so that one can easily know the time by looking down. (III) Wristwatches come in various shapes and sizes, but all have one thing in common: a band or strap with which they may be attached to the wrist. (IV) This band or strap may bemade of metal or leather, or sometimes from plastic. (V) Moreover, some people still prefer to use old-fashioned watches.