20ml headspace gas chromatography with PTFE septa Alibaba 2021 - 10 - 25 Vials Cap Septa for GC HPLC – 2ml Amber Sample Screw Vials. 20mL, Amber Glass, 22.5*75mm, 20mm Beveled Edge, Rounded-flat Bottome, Short Neck, Crimp Top Headspace Vial suitable for PerkinElmer, 100pcs/pk. Silver, 20mm Open Top Aluminum Crimp Cap, pre-assembled with 20*3.0mm Natural PTFE/White Silicone Septa. 100pcs/pk.