Never before has a a GMT movement been used in conjunction with a split timing bezel, counting down then up from mission start over a duration of 24 hours. So original is it’s functionality it has been granted a patent.
Count down to an event start up to 12 hours in the future: Rotate the internal bezel so that ‘H’ (mission start, H-hour) is the required number of hours in advance of the GMT hand.
Your mission countdown is now set and running. The number of hours until the event starts can be read directly off the inner bezel using the tip of the GMT hand.
Illustration shows 6 hours count down to ‘H' event start.
When the GMT hand reaches ‘H', mission count up begins around the second half of the inner bezel. Illustration shows 4 hrs elapsed mission time.
This is particularly useful to rendezvous a number hours after mission start and for single or multiple time sensitive objectives up to 12 hours after mission start.
Alternatively, set inner bezel so ‘H' is aligned with the GMT hand to count up to 12 hours from an event.
EG. Count down to an event 40 minutes in the future:
Turn the outer bezel so that the number 40 is aligned with the minutes hand.
The number of minutes until event start (red 12h triangle on bezel) can be read directly off the scale on the outer bezel.