On February 10th 2012 the game hosted a server stress test event that aimed at testing out server capacity limits. To get as many players as possible to participate (and thus, push servers to their limits) this special helmet was promised to anyone who would participate on the event on the US EAST server during the specified time. It was said that the helmet would only ever be given out to those players and not be unlockable in any other way.
The helmet was sent out to players on March 14th 2012.
In-game Description Edit
Standard helmet. An Overmatch ArmetX, battle-damaged from fighting in the beta