A compass is used for underwater and topside navigation. Your instructor will teach you how to navigate with a compass during your open water dives.

Compasses must be held level to provide an accurate reading. The best compasses are filled with water, which dampens needle movement and prevents the compass from breaking under the pressure encountered under water.

The bezel is used to set your desired heading. Two sets of index marks protrude from the inside of the bezel. When the north arrow is aligned with the double index marks, you are traveling towards your heading. To travel back to your starting point, turn around until the north arrow aligns with the single index mark.