When we were younger, we all learned that you lose a considerable amount of heat though
your head. In the underwater environment, that issue still applies. Wearing a hood
will give your head thermal protection from the cold, along with protection from coral and
other sharp objects. Hoods are available in a variety of thicknesses. Dry suit
divers have the option to wear drysuit hoods, hoods without bibs, while wetsuit divers
prefer hoods with large bibs. These bibs tuck into the wetsuit and minimize water
movement. Other common hoods have skin-in seals that prevent water movement
and vents to allow air trapped in the hood to escape.