Snorkel

A snorkel is a tube about a third of a meter (one foot) long, usually J-shaped, fitted with a reasonably comfortable mouthpiece, and constructed of rubber or plastic, used for remaining submerged while diving in shallow waters.

Some snorkels have float-operated valves attached to the end away from the user's mouth to keep water out when the swimmer submerges. Most, however, are allowed to flood, and the water expelled by a sharp exhalation through the snorkel when the swimmer returns to the surface.