40 mL Septa Vials. Standard 40 mL septa vial is clear borosilicate glass with 0.125 in. thick, I-CHEM blue, PTFE/silicone septa in an open-top 24-414 polypropylene cap. The I-CHEM molded-in septa retainer ring holds the septa securely in place without bonding to the cap, so septa can be removed and replaced as needed. Economy Certified Glass