Electric pipe caps, also known as electric pipe inner plugs or inserts, are widely used, easy to install, and commonly found in everyday life.

Power conduit caps in hot solvents, some thermoplastic plastics will be attacked and dissolve, 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 great potential. For high-demand products such as power conduit plugs and stoppers, when using solid powder or granular additives, they must be ground on a three-roll mill equipped with plasticizers and plastic valve caps.