This specification covers virgin, unfilled, polytetrafluoroethylene (PTFE) in the form of molded rods, tubes, and shapes. This specification does not apply to product over 12 inches (305 mm) in dimension parallel to the direction of applied molding pressure, rods under 0.750 inch (19.05 mm) in diameter, and tubes having wall thickness under 0.500 inch (12.70 mm). These moldings have been used typically for parts, such as seals, bearings, insulators, and back-up rings, requiring chemical inertness and good mechanical and electrical properties up to 260 degrees C (500 degrees F), but usage is not limited to such applications.