Bungie has finally confirmed, after months of speculation, what that damned X button does in Halo 3 - and apparently you'll be using it in the multiplayer beta next month as well.
The secret function of the little blue button is for deploying equipment and you see three different kinds in action in the latest video documentary.
While the developer doesn't specify exactly which pieces of equipment are exposed in the video, we're guessing that the new bubble shield, trip mine and mobile gravity lift are all assigned to the fancy new X button functionality.