Aijiren’s 18mm Screw Top Headspace Vial is available in 10ml, 20ml, amber glass and clear glass. And the caliber of Headspace Vial is Screw thread, which is convenient for sealing and opening the headspace bottle. At the same time, the Screw Top Cap of Aijiren’s Headspace Vial has a center hole, which is convenient for the automatic injection needle to enter and exit. The thickness of Septa is easy to pierce and has a tight seal.