Power conduit caps, also known as internal plugs or inserts for power conduits, are widely used, easy to install, and commonly found in everyday life.

Electric conduit caps in hot solvents may be attacked and dissolve by some thermoplastic plastics, such as polyethylene dissolving in xylene. Thermosetting plastics cannot be dissolved in solvents. As a source of rapid industry development, the plastic bottle cap industry has immense potential. For high-demand products like electric conduit plug and insert, when using solid powder or granular additives, the blending must be done on a three-roll mill equipped with plasticizer and plastic valve caps.