Opto-aud displaying the Enterprise

The opto-aud was used by Theela on the second planet of the Taurean system to find suitable men from whom to drain their vital energy.

The opto-aud was a very advanced device. It could display images and information from people and/or ships at distances as far as twenty light years. It was activated by tonal control and revealed anything that it was asked. (TAS: "The Lorelei Signal")