A hood is mostly made of neoprene and is, as the name says, a hood, which covers the head completely. You need this above all if you dive in soiled and/or cold bodies of water. Thereby this headgear protects you against dirt, cold and also injuries to some extent.
Since it does not offer enough protection during certain dives which are linked to higher risks, you should rather wear a helmet then. This applies to cave diving, wreck diving and current diving above all.
Important tip regarding a hood
This accessoire closes off the ears, so that pressure compensation only takes place partially in the ear. In order to avoid suffering from a barotrauma, you should imperatively perforate the hood at the height of the ears, hence make a small hole in it.
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