4. There are two kinds of colors, glass and amber. 5. Precise bottle neck size, ensure autosampler handle correctly. 6. Suitable for Thermo Sciebtific, Beckman, Gilson, Knauer, Spark, Varian, VWR(Merck)/Hitachi, PerkinElmer autosamplers. Features 1. 10mm screw vials can be used on all common autosampler. 2. Standard narrow neck design for GC