These type of watches were the most common type of watch from their development in the 16th century until wristwatches became popular after World War I. Pocket watches generally have an attached chain to allow them to be secured to a lapel, waistcoat, or belt loop, and to prevent them from being dropped. There are two main styles of pocket watch, the hunter-case pocket watch and the open-face pocket watch. An open-faced, or Lepine watch, is one in which the case lacks a metal cover to protect the crystal - like the one in this fun new jigsaw puzzle. A hunter-case pocket watch is a case with a spring-hinged circular metal lid or cover, that closes over the watch-dial and crystal, protecting them from dust, scratches and other damage. Now that you know a bit more about these types of time pieces click start and enjoy today's challenge. Have fun!