These are not just typical chrono watches since you can also check the time of the cities you're going (hence the word World Time) which are visible around the steel case such as London, Paris, Bangkok etc etc. In order to do that there's a button on the left side to press and let the upper arms on the top left to show the time of the city that you currently are in. And if you're in some part of the world where summer and winter time is significant then the lower right arm will let you set the timing automatically without the hassle for you to add or minus one hour from the current time.
I think by having the other time zone indicator is quite helpful coz you don't have to worry about changing the timing again and again once you've landed on the other side of the country. And if you look closer, the face dial of the watches has a silhouette of the world map. Isn't that pretty neat? So cool...
[pix from watchismo]