Technology developed at Stargate Command which can block a Prior's advanced, hok'taur-like abilities. A particular frequency, reached via a small remote control, must be active and transmitting for a Prior to be impaired.
The prototype model's frequency is not sufficiently strong enough to fully block a Prior from accessing ascended powers, as enough concentration can make the device useless. But it preoccupies a Prior enough that he can be shot and killed in the interim.
The range of the technology is not known. The first test was performed with the Prior standing almost directly above the device.
The Fourth Horseman, Part 1 - Using knowledge acquired from their encounter with Khalek, S.G.C. completes designs for a prototype Prior inhibitor.
The Fourth Horseman, Part 2 - The Prior inhibitor is tested on the Sodan homeworld and, to a large degree, works.
The Shroud - The team captures a Prior-ized Daniel Jackson, and keeps him under control with an inhibitor ... for a little while.
Dominion - Baal uses stolen inhibitor technology to keep Adria's powers at bay after he captures her.