Headspace screw neck vials N 18. More convenient, consistent, and safer sealing process compared to crimping (better reproducibility). No risk of inaccurate or inconsistent crimp results. Due to thinner septa suitable for SPME as well as for Headspace. Often used on CTC Combi PAL and identically constructed autosamplers as well as on PerkinElmer instruments. Please note that this screw neck vial N 18 cannot be used in combination with PP screw closure 702115 or any other plastic screw closures with 18-400 thread design.