vial headspace with ptfe liner pp cap manufacturer ptfe caps for 20 ml vials | Sigma-Aldrich 27022. black polypropylene cap, 24-400 thread, PTFE/silicone, septum thickness 3 mm, for use with 20, 40, or 60 mL vial, pkg of 100 ea. Supelco. pricing. SDS. 27093-U. black phenolic hole cap, thread for 8-425, PTFE/silicone, septum thickness 1.5 mm, for