Lumus has long developed heads-up displays for the US military, but now its using a developer kit called the DK-40 to bring its HUD tech to wearables outside the battlefield. The contraptions first stop was the CES show floor, so we couldnt resist putting our fingerprints all over it. The key feature of the DK-40 is the optical engine, which eliminates the need for a thick piece of glass to house a substantially-sized prism.