How to use diver's bezels

The diver’s bezel is used to indicate elapsed time -in other words, measuring the amount of time which has passed, for up to 60 minutes. For safety underwater, the bezel only turns in an anti-clockwise direction, meaning that it can only ever show less time, not more.
To set the divers bezel, begin by aligning the zero mark, the triangle symbol, of the rotating bezel with the position of the minute hand. Then, turn the bezel anticlockwise to indicate the desired duration of time.
For example, setting the rotating bezel to 40 minutes past the hour when it is 10 minutes past the hour would provide 30 minutes of time underwater. The time will have elapsed when the minute hand reaches the zero mark, the triangle.