Certified to contain<50 ppb total organic carbon standard 40 ml septa vial is clear borosilicate glass with 0.125 in. thick, i-chem blue, ptfe ilicone 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...<>50>