A pocket watch (or pocketwatch) is a watch that is mae to be carried in a pocket, as opposed to a wristwatch, which is strapped to the wrist. They were the most common type of watch from their development in the 16th century until wristwatches became popular after World War 1. The display is traditionally analog. Pocket watches generally have an attached chain to prevent them from being dropped, secured to a waistcoat, lapel, or belt loop. The chain or ornaments on it are known as a fob. They often have a hinged metal cover to protect the face of the watch; pocketwatches with a fob and cover are often called "fob watches". Also common are fasteners designed to be put through a buttonhole and worn in a jacket or waistcoat, this sort being frequently associated with and named after train conductors.