Vials have a 40% larger opening for easier sample preparation. Features. 9mm screw vials can be used on all common autosampler. Standard narrow neck design for GC and HPLC. 9mm wider opening for easy puncture. 9mm PTFE/silicone septa, has excellent chemical inertness, acid and alkali resistance 9mm Short Thread HPLC Vials--Aijiren Vials for HPLC/GC