DIELECTRIC AND EXPANSION JOINTS, a type of PIPES.
Dielectric and Expansion Joints are a type of Pipes.
Manufacturers differentiate dielectric joints according to their intended function, as that purpose shapes how industry players compete. Expansion joints, often called bellows, are grouped by the materials from which they are made because different materials suit different uses. Also included here are slide plates, simple devices used to reduce friction, which are typically fabricated from Teflon.