The polymer can be filled with a reinforcing substance, such as 10-40% filled with glass or carbon fiber. [0049] Plastics can be extruded with outer diameters of, for example, 4 mils (100 ??m) or less, and inner diameters of 2 mils (50 ??m) or less. [0050] Glass and suitable plastics can be drawn to suitable inner and outer diameters.