Description from website.  Never used.  Received as a gift.  Have not tested.  

xxxhttp: //www.charlottevanderwaals.nl/en/products/waals-world-watch-abs/item11

"The world clock with all 24 timezones"

size ø 5 x 5 cm.
material: hard plastic 
color: black
movement: Quartz Seiko Japan, detachable 
packaging: feldbag in special designed box with paper wrap
title and patent number on the back

The Waals World Watch has 12 sides. Each side has the names of 
2 major cities, with differences of exactly 24 hours (AM and PM). Altogether the 24 cities represent the 24 Global Time Zones. Based on Standard Time.

To find the local time in a desired timezone, turn the clock so that the city representing that timezone is at the top.
To determine if the hour is AM or PM: "In the west the time is less, in the east time increases".

The Waals World Watch is useful next to the computer and the phone, on a journey, for international business or when friends, family or lovers are abroad.