Logitech 3D MOUSE & HEAD TRACKER Technical Reference Manual page 21

Installation and Setup
The second device, which appears in Figure 2-5, shows a user wearing
® ®
virtual reality, Stereographics Crystal Eyes VR glasses and the 3D
Mouse transmitter. These glasses, designed by the StereoGraphics ®
company, function as a receiver-three microphones are imbedded in
the glasses frame.
The Crystal Eyes ® VR glasses allow the user to see a virtual, holographic
image that appears to float in front of the host computer's monitor. As
the user moves his/her head, the holographic image adjusts to the user's
head movements.
Figure 2-5. Custom Stereographics® Glasses with Microphones
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