PTFE as the main material. Has excellent chemical stability, corrosion resistance, sealing, lubrication is not high viscosity and good aging endurance. Long-term work at a temperature of -180 ℃ to +250 ℃, in addition to the molten metal and liquid sodium fluoride,  the ability  of all other  chemicals, boiling water is not from the king of change. Competitions are not allowed pollution is mainly used for environmental sanitary conditions, corrosion, etc., the line speed is high, easy to wear and other conditions.