. . "It is typically made of an injection molded, filled polymeric material such as polysulfone, polyphenylene sulfide, polyester, polyetherimide, acrylonitrile-butadiene-styrene, polystyrene, polyamide (nylon) or polycarbonate resins filled with such materials as glass beads, fiber glass and mica (e.g., 20 weight percent fiberglass and 20 weight percent mica and 60 percent polymer resin)." . . .