GMT, Worldtimer, GMT Chronograph
Operating instructions2
24-HOUR ‘WORLDTIMER’ DISC 
(calibres 8938-8939 – fig. XIII) 
Thanks to the ‘24-hour’ disc, travellers can read the time in different 
time zones symbolised by cities or geographic areas on the dial.
Setting the time and the date:
Pull the crown out to position 3. By turning the crown, move the 
minutes hand and the 24-hour universal time disc forwards until they 
indicate the UTC (Coordinated Universal Time) time. The display of 
the 24-hour universal time must be set in such a way that the time 
 
corresponding to the different time zones (represented by cities or 
geographic areas on the dial) is correct. 
Push the crown back to position 1 to start the movement.
Pull the crown out to position 2. By turning the crown, move the hour 
hand forwards or backwards in one-hour increments to set the date, 
then position this hand on the time that corresponds to the time zone 
selected. As the date will change at midnight, make sure you set the 
hour hand in the correct half of the day!
List of cities or geographical areas with summer time: London, Bienne, 
Athens, Sydney, Auckland, Alaska, Los Angeles, Denver, Chicago, New 
York, Rio, Azores.
For these cities/geographic areas, add an additional hour to the hour 
indicated when summer time is in effect.