Interface Headset

An interface headset (インタフェイスヘッドセット) is a small device, worn when piloting an Evangelion unit.

Purpose
Judging by the name given to the device, it is assumed that the interface headset aids the pilot in interfacing with their Evangelion. However, the exact function which this device carries out is never explicitly stated. Pilots are seen, however, using Evangelions without a plugsuit, whereas they almost always wear an interface headset. This implies that the headset is a more critical component of piloting the Evangelion.

It should be noted that interface headsets are not used when piloting simulation bodies. Additionally, Shinji did not wear one in parts of The End of Evangelion.

Design
The interface headset seen most often is composed mainly of two pieces which sit in the pilot's hair, near their temples, and are connected by some type of hairband, which is usually covered by the hair itself.

Other designs
In the other designs, the headsets' receptors are in slightly different positions than the regular design. It is not known if this has any functional implications.
 * Asuka, in both Neon Genesis Evangelion and during her Evangelion Unit-03 test in Evangelion 2.0, wears an interface headset which is slightly modified to be more like hair clips.
 * Mari's headset is also slightly different, more resembling a headband.

Name
Many English-speaking fans refer to the interface headset as "A10 nerve clips", rather than its official name. However, aside from Asuka's, none of the headsets are actually composed of hair clips; additionally, there is no partial or complete evidence that they are directly related to A10 nerve synchronization.