"Suitable materials include stainless steel, titanium and its alloys, cobalt-chromium-nickel-molybdenum-iron alloy (commercially available under the trade designation ELGILOY???), carbon fiber and its composites, and polymers such as liquid crystal polymers, polyetheretherketone (PEEK), polyimide, polyester, high density polyethylene, PEBAX???, various nylons, and the like." . . . . . .