1)9mm screw vials can be used on all common autosampler. 2)Standard narrow neck design for GC and HPLC. 3)9mm wider opening for easy puncture. 4)Clear, type 1 class A borosilicate glass. 5)9mm PTFE/silicone septa, has excellent chemical inertness, acid and alkali resistance. 6)9mm screw black open top pp cap.