They are standard vials for GC/ HPLC and designed to work in a variety of Autosamplers requiring narrow neck vials. The vials are preferentially used on instruments of the following manufacturers: Beckman, CTC, Gilson, Knauer, Shimadzu, Spark, Varian, VWR (Merck®)/Hitachi, etc. Feature. 32 *12 mm, 2ml, screw neck; The original, narrow neck size