1. 8mm screw vials can be used on all common autosampler. 2. Standard narrow neck design for GC and HPLC. 3. 8mm wider opening for easy puncture. 4. 8mm PTFE/silicone septa, has excellent chemical inertness, acid and alkali resistance. 5. 8mm screw black open top pp caps. Technical Parameter. 1. 8-425 Thread Small Opening Vials ND8