When Achelos Helmet is worn, Conduit Power II and Dolphin's Grace I is applied to the player. Both effects are immediately removed if the helmet is taken off.
It can be worn in place of the helmet of a different armor set to achieve the other armor's full set bonus.
Achelos Helmet will also provide its own oxygen, meaning that it will prevent the player from drowning, along with preventing the player from taking damage in dimensions with unsafe atmospheres- such as Vox Ponds and Lunalus.
Achelos Helmet can be obtained as a drop from the following mobs: