Spring washers ground heatsink type drop-ins (that lack an outer spring), such as TorchLAB. For 18m E applications, place between body and head. For 22mm P applications, place at the bottom of the P60 socket before installing P60 dropin.
These spring washers complete the electrical path between the body and drops in (the job was traditionally done by the outer spring).
This item is made in the USA.