Headspace screw neck vials with precision thread, ND18. Vials, closures, septa and kits. Special pre-cut septa (silicone layer is slitted but PTFE remains intact) for safe penetration of the sensitive SPME phase with hardly any coring. Tested and approved by CTC for their Combi PAL (Gerstel, Atas, Aijiren), also recommended by Aijiren for their