“ A strange device, constructed from an odd technology. ”
psychic nullifier is a miscellaneous item in .
The psychic nullifier is strange device, possibly the product of an
alien technology. It blocks telepathic or psychic commands.
It is placed on the head of a
psyker to disable or prevent them from using their powers. A psychic nullifier also blocks incoming telepathic attacks when worn by a non-psyker, such as those frequently experienced in the Corridor of Revulsion. The Vault Dweller can obtain one to aid in passing through the corridor on the way to the Master.
Gideon and the other three psykers each have nullifiers in the game. The Vault Dweller can kill Gideon or persuade him to give the "helm". The others can be obtained either through theft or killing them.
p.128: Fallout Official Survival Guide " Psychic Nullifier: A strange device, possibly the product of an alien technology. It blocks telepathic or psychic commands."