A disk with a triskele on it that the Hale family used to train their children to control their power. 

Derek used to recite a mantra of Alpha, Beta, Omega to help himself keep from shifting on a full moon. The triskelion itself is simply a trinket, used to help focus one's mind.

Kate was led to believe that it had magical properties that would help her control her shift, but Peter was pleased to disabuse her of that notion.

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