G.I. Joe Sigma Six The Sigma 6 toy line served several purposes for Hasbro. First, it allowed them to depart from the classic 3 ¾-inch format of the A Real American Hero series of the 1980s; most Sigma 6 action figures stand at approximately 8 inches (200 mm) and have more articulation. Second, the new series offered them the chance to streamline the story and characters, stripping away old continuity and "rebooting" the franchise with younger versions of the cast - similar but different to their 1980s namesakes - rendered in the popular anime style.