Standard equipment on all Type 89 (formerly known as Type 102) TARDISes, this device ties in with the Telepathic Circuits and the State of Temporal Grace Circuits to "freeze" any intruder whose bio-rhythms don't correspond to pre-programmed list of "friends." The victim is trapped in a spare dimensional stasis field, which can only be deactivated from the Control Console. Depending on the setting the intruder might be able to speak.