The Helmet of Second Sight is a mystical artifact from Atlantis. It was the helmet of Aticleas.
The helmet was in Eddy Owen's private collection at his home in England. But Hammer stormed the house and took the helmet from him.
The helmet was then delivered by Major Maxim to the Hammer Fuhrer, who was transformed into Aticleas when the helmet was brought together with the Shield of Immunity and the Sword of Sovereignty.
The three pieces of the armor were then washed away by the ocean when Hammer Island was destroyed.