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 helmets are not used when piloting simulation bodies. Additionally, Shinji did not wear one in parts of The End of Evangelion.