本规范涵盖了挤压棒、管和型材形式的未填充聚四氟乙烯（PTFE）。这些产品通常用于零件，如要求化学惰性和尺寸稳定性高达500 mDF（260 mDC）且机械和/或电气性能优于AMS 3656的绝缘子和套管，但使用不限于此类应用。对于不需要介电性能和射线照相检查的密封件、支承环和轴承等应用，建议使用AMS 3678/1 B级。

This specification covers virgin unfilled polytetrafluoroethylene (PTFE) in the form of extruded rods, tubes, and shapes.These products have been used typically for parts, such as insulators and bushings requiring chemical inertness and dimensional stability up to 500 \mDF (260 \mDC) and better mechanical and/or electrical properties than AMS 3656, but usage is not limited to such applications. for applications such as seals, back-up rings and bearings that do not require dielectric properties and radiographic inspection it is recommended to use AMS 3678/1 Grade B.