1.High temperature resistance: PTFE liner is recommended to be used within 180 °C, PPL liner is recommended to be used within 250 °C. 2.Low temperature resistance: at -196 °C could keep 5%. 3.Corrosion resistance: acid & alkali resistant, strong alkali, aqua regia and various organic solvents resistant. 4.Insulation resistance: dielectric properties are independent of temperature and frequency. 5.High lubrication: The lowest friction coefficient in solid materials. 6.Non-adhesive: no sticking to any substance, good self-lubricating, the friction coefficient in solid materials is 0.04. 7.Non-toxic: It is physiologically inert, can be implanted into the human body, is resistant to aging, and can be used in the atmosphere for a long time. 8.Anti-pollution: the metal element has a low blank value and the lead content is less than 10-11g/ml.