3088923 Green closed top screw cap with rubber/PTFE septa, Ø 8 mm 4 ml sample vials made from pure, class I borosilicate glass. solutions - Chromatography Consumables Resources and Information. aluminum crimp seals . RI detectors, PTFE/Synthetic Red Rubber septa 1 .5. ST1 White silicone/red PTFE. 57. 1 .0. Seals in 18 and 20mm Caps.