The bezel on Longitude carries a sixty-minute scale and a luminous pip at twelve. It turns, so it can mark the start of anything you want to time.
Setting it
At the moment you start, turn the bezel until the pip sits over the minute hand.
Reading it
From then on, the minute hand points to the elapsed time on the bezel scale. Twenty minutes later it points to 20, whatever the hour.
Why it turns one way
The Longitude bezel turns in one direction only. An accidental knock can only make the elapsed time look longer, never shorter: a small design choice with a safe failure.
