At a SWAG, around tech Level ten (TL10). Early units will have very short range transmitters to attach to wrist comps, with the wrist comp supplying the vocal transcription/orders recognition. The displays will be thermally powered by the heat of the eye, and will provide passive responses only. At TL 11, the range of the comp interface will be increased, but it'll still be a passive display. From TL12, it'll be a fully responsive system using menu driven software by eye movement, and not requiring an external computer, merely a transceiver array to communicate with other systems. Cost for TL10 will be from Cr50k, dropping to around Cr10k at TL12.