This specification covers one grade of polytetrafluoroethylene resin in the form of extruded rods, tubes, and shapes. These products have been used typically for parts, such as seals, back-up rings, and bearings, requiring chemical inertness and dimensional stability up to 260 degrees C (500 degrees F) and better mechanical and/or electrical properties than AMS 3656, but usage is not limited to such applications.