Crimp seals with PTFE/silicone septa diam. × total thickness × PTFE thickness 20 mm × 3 mm × 5 mil, silver aluminum seal (10mm opening), open center, (silicone blue transparent/PTFE transparent), pkg of 1000 ea; find Supelco-SU860010 MSDS, related peer-reviewed papers, technical documents, similar products & more at Sigma-Aldrich