Wraith mind manipulator
From The Stargate Omnipedia
Experimental device developed on M1B-129 by the Wraith for the purpose of improving the mind manipulation process. The Wraith, who largely hunt by manipulating the minds of their prey, believed they may do so more effectively by studying the process themselves.
The technology projects an electromagnetic field which prevents normal radio communication. The unit fluctuates in systematic intervals on an ultra-low frequency. Actuator coils lie inside the membrane. A primary conduit, which leads directly into the core, deactivates the device when it is removed.
KEY EPISODE
Phantoms - Sheppard's team visits M1B-129 to investigate the loss of a reconnaissance unit who has since gone mad encountering a Wraith device.