PTFE Balls can be filled with Glass fiber, Carbon, Graphite, Bronze and Colors
PFA (PerFluoroAlkoxy) tubing offers similar properties to FEP, but is considered more of a premium resin. PFA is preferred when extended service is required in hostile environments involving chemical, thermal, and mechanical stress
Polyimide refers to a class of synthetic polymers. Adding polyimide produces a PTFE compound that is lower in friction than all of those previously described. It is non-abrasive, making it a good choice for applications involving softer mating surfaces like steel, aluminium, or other plastics. Polyimide filled PTFE therefore suits dry running and stop-start applications particularly well. However, polyimide is the priciest of the PTFE fillers.