The telekinetic suppression collar was a device designed to prevent an individual from exercising telekinesis. Most telekinetic suppressors were fairly bulky devices.
Eris, a Dominion spy, was supposedly fitted with a telekinetic suppression collar after her "capture" by the Jem'Hadar. In reality, this collar was little more than a collar with a complex locking device. (DS9: "The Jem'Hadar")