Bi-metal crimp closures support transportation of the vial via magnet, as for e.g. in the CTC Combi PAL, the Shimadzu AOC 5000/6000 or the Gerstel autosampler. They are generally more difficult to crimp/decap which is why Headspace screw neck vials N 18 may be a more convenient alternative. We recommend Silicone/PTFE septa as the optimal choice for Headspace, as they offer a temperature resistance form -60 °C up to 200 °C, highest analytical purity and excellent penetration properties. Septa are assembled, caps are ready-to-use. Septa are shown for illustration purposes only, images upside down.