A knob used to wind a mechanical watch and to set the time and/or other functions. Some watches have more than one. There are two types: screw-down (locked) and push-in (non-locking). The typical location is 3 o’clock on the case flank, however, the crown can be located at 12 o’clock, between 4 and 5, on the caseback, or on the left side of the case. Old pocket watches used a winding key instead of a crown.