Plugsuits are form-fitting full body suits resembling a diver's wet suit, worn by Eva pilots together with their Interface Headsets in order to increase their synchronization with the Evangelions. Although helpful, plugsuits do not appear to be essential to pilot an Eva, as there have a few occasions when Shinji piloted without one. It is stated, however, that a plugsuit increases the pilot's synchronization ratio by cutting down on interference.