A small device attached to the forehead of the user that enhances the limited Telepathic Avatar ability. Sheppard used such a device to allow himself to remote control McKay's body in order to pass his 'fitness test' and earn the transformation into a Lantean.

Sheppard hadn't developed enough to be able to attain the ability unaugmented. While his transformation into an Alterra was complete, he wasn't 'old enough' to have developed most Edeva skills.