Home » News » HPLC Septa Cap » Sigma PTFE septa cap distributor Septa | Sigma-Aldrich red PTFE/white silicone, diam. × thickness 10 mm × 0.060 in., for use with 2 mL, 10/425 thread, large opening vial, pkg of 1000 ea. Pricing. 27097-U. red PTFE/white silicone, diam. × thickness 8 mm × 1.5 mm, pkg of 100 ea. Pricing.