Watches and clocks with the memento mori motifs were not uncommon, dating from the mid 17th Century to the 1930s. This early Verge silver skull pivots at the top of the cranium, whereas others pivot from the jaw. There are others created that fold open at the top of the head with enamel and diamonds, but pieces like these are extremely rare and command a high price. Examples exist from Switzerland, France, Germany and England. As written by the Taft Museum:

The skull and watch are part of the standard subject matter of 17th-century vanitas still lifes. Vanitas is from the Latin for “emptiness” or “untruth,” from which comes the English word “vanity.” Such pictures depict objects that have an underlying moral message—usually about the fleeting nature of physical reality. Therefore, it is not surprising that the skull and watch, two reminders of the passage of time, should merge in a single object. The use of the skeleton hand, however, is unusual.”