A substance that is not a conductor of direct electric current, a dielectric is an insulator, rather than a conductor. A dielectric permits the passage of the lines of force associated with an electromagnetic field, but does not conduct the current. As dielectrics, however, can sustain an electromagnetic field, they are commonly used in capacitors and between wires in a cable. Dielectrics include rubber, gutta percha, wood pulp, polyethylene, polyvinyl chloride, flouropolymer resin, and Teflon