Probic vent

The Probic vent was an essential part of all cloned Sontarans.

Information
At least partially artificial, the Probic Vent took the form of a small metallic tube attached to the back of the Sontaran's necks. This vent was normally used by the Sontarans as a way of directly feeding off energy to "recharge" rather than eating (as the latter was slower). Raw plasma was fed directly into the vent to nourish them. (DWM: The Betrothal of Sontar)

The Vent was also a major weakness, since a blow to the Probic Vent could knock a Sontaran unconscious or even kill them. (DW: The Time Warrior) A lesser blow could cause them pain and/or stun them (DW: The Sontaran Stratagem). An arrow (DW: The Time Warrior) or a thrown knife (DW: The Invasion of Time) would almost certainly prove deadly.



The Sontarans did not find it a problem, however, since it meant that they must always face their enemy in battle and could not be cowardly and run away. (DW: The Time Warrior / The Sontaran Experiment).

However, some people occasionally found ways to disable Sontarans from in front of them: for example, the Tenth Doctor momentarily disabled General Staal using a squash racket and a ball by rebounding the ball from Staal's Teleport pod and onto Staal's Probic Vent. (DW: The Sontaran Stratagem). Donna Noble used a hammer to hit a Sontaran on the probic vent when it had its back turned. (DW: The Poison Sky)

The placement of the vent may have been deliberate, as it would force the Sontarans to face their enemies.

List of weapons used to strike a probic vent

 * A Metal pole. (DW: The Time Warrior)
 * A Bow and Arrow. (DW: The Time Warrior)
 * A Knife. (DW: The Invasion of Time)
 * A Squash ball. (DW: The Sontaran Stratagem)
 * A Hammer. (DW: The Poison Sky)
 * A High-heeled Shoe. (SJA: The Last Sontaran)