Pillar No. 4519 PTFE fiber covers the inner core which is made of spun carbon fiber threads. This packing is a combination of the excellent features of PTFE in chemical resistance and the heat resistance and elasticity of carbon fiber. The low friction surface of this fiber makes it suitable particularly for adjusting valves in which smooth revolution of the valve rod is especially important. Performance: pH 0 to 14, Temperature 260oC , Pressure Class 600, Fluid Oil solvent, acid, alkali. Applications: For valves, control valves.