Jon describes how to use the the 4th hand for military time.
You can also use the bezel for an hour offset to track a second timezone. When working with the UK years ago I used a GMT hand to track their time. You see, by my lunch time they were going home for the day, so I only had 4 hours to get to/from them what I needed. When I looked at where the 4th hand was pointing to on the bezel I knew what time it was in the UK.