The Blue Filter, used in tandem with the A/V Calibration tool that comes in the Legendary and Limited Editons of Halo 3, is now available at the
Bungie Store. The Blue Filter comes free with any order from the Bungie Store, make sure you add it to your cart though, because this item only has use for folks with the Legendary or Limited Editions of the game, due to its working partnership with the A/V Calibration tool
For a guide on how to use the Blue Filter once you receive it,
click here.