Ptfe Liner found in: PTFE Liners, 9mm R.A.M. Caps with PTFE Liner, PTFE Cap Liners, PTFE/Silicone Liners, Cap, Phenolic, PTFE Liner, 38-430, Pre-Assembled.. Scientific glass environmental sample containers. The PTFE liner is bonded to the cap so it won't fall out or become separated from the cap.