Crimp seals with PTFE/silicone septa silver aluminum seal, pressure release (open center), PTFE/silicone, diam. × total thickness × PTFE thickness 20 mm × 2.5 mm × 5 mil, pkg of 100 ea; Synonyms: PK100 20MM PRESSURE RELEASE SEAL,PTFE/SILICONE LINER; find Supelco-27455U MSDS, related peer-reviewed papers, technical documents, similar products & more at Sigma-Aldrich