. . . "Examples of materials for deformable sections include neoprene, nitrile, polyisoprenes, fluoroelastomers, ethylene/acrylics, silicones, butyl rubbers, SBR, EPDM, VITON, combinations and derivatives thereof, and other materials, e.g., as in the Handbook of Plastics and Elastomers." . . . . . . .