Standard opening septa closure manufacturer-Aijiren HPLC Vials black polypropylene hole cap, thread for 8-425, PTFE/silicone, Top Hat (septa and closure designed to fit together tightly), for use with 2 mL vial, 4.6 mm opening, pkg of 100 ea: Pricing: 27262: black polypropylene hole cap, thread for 8-425, PTFE/silicone, septum thickness 1.5 mm