Screw Vial, Headspace, Flat Bottom manufacturer / supplier in China, offering 20ml Headspace Vial 18mm Precision Screw Thread Neck ND18 Clear/ Amber Round Bottom, 22ml Storage Vials, Borosilicate Glass, with Phenolic Screw Cap, 5ml Storage Vials, Borosilicate Glass, with Phenolic Screw Cap and so on.