Also known as: インタフェイスヘッドセット
A device worn on the heads of Evangelion pilots in addition to their plugsuits.
A standard interface headset consists of a low-profile headband with a pod at either end. The headset goes around the back of the wearer's head from underneath the hair, with only the two pods appearing in plain sight.
It is likely due to a misunderstanding of this construction that they are sometimes (mistakenly) referred to as "A10 nerve clips", being confused for Hairclips. There are no canonical materials suggesting that the device has anything directly to do with A10 nerve synchronization, and only Souryuu Asuka Langley wears an interface headset in the form of an actual pair of separate hairclips.