Multi-Zone watches – show the current time in two or more time zones simultaneously.
World timer watches – watches with a dial usually on the outer edge of the watch face that tells the time in up to 24 time zones around the world.  The time zones are represented by the names of the cities printed on the bezel or the dial.  The wearer reads the hour in a particular time zone by looking at the scale next to the city that the hour hand is pointing to.  The minutes are read as normal.