Gauges
dive watch
Timing Device
You'll learn later in this course that monitoring your depth and bottom time is important for preventing an injury called decompression sickness, or the "bends." For this reason, you need to carry a timing device.

The most popular timing device is a watch. Watches for scuba diving are water resistant to a depth of at least 300 feet, and have a rotating bezel. Before descending, the bezel is rotated so that the minute hand aligns with the zero mark on the bezel. When you surface, record where the minute hand points to on the bezel, which is your dive time.

Electronic dive timers are also available. These devices automatically begin timing your dive when you descend, and stop timing when you surface. This eliminates the risk of forgetting to set your watch before descending.