The O3 is a full electronics upgrade for the eMagin Z800. 

The O3 delivers increased video performance in the 2D and frame sequential video modes than the standard factory boardset and adds dual input support for separate left and right video channels.  Support for the the Z800's 6 DoF tracker has been disabled but the Z800 will support a wide variety of 3rd party trackers from Intersense and Ascension.