Pocket watch, Barent van der Cloesen, c. 1690 - c. 1710
Watches with an openwork or ajouré case often have an alarm, since the perforations in the case allow the sound of the bell to be heard. The movement is nevertheless well protected against dirt and dust because it has an inner and an outer case. The Dutch made this type of watchcase beginning around 1680: the exteriors were finely decorated with engraving. The openings in this case have a minutely executed pattern.