Headspace Vials, Caps and Kits | Thermo Fisher Scientific - RU 2021 - 11 - 19 18mm Clear Headspace 20mL Screw Vial, Round Bottom, (20-HSV) Silver Steel Screw Cap, 8mm hole (18-MSCST201) 18mm Blue Silicone/ Natural PTFE. 125. 20-CVCBT3-CP. 20mL Clear Headspace Crimp Vial, Beveled Edge, Round Bottom, (20-CV) Silver Aluminum Crimp Cap, 8mm hole (20-AC-CBT3) 20mm Molded Blue Chlorobutyl/Gray PTFE.