2ml Amber Screw HPLC Vials--Lab Vials Manufacturer 2ml Amber Screw HPLC Vials, caps, septa, and inserts working as a whole to prevent sample degradation and loss of samples caused by evaporation. Screw thread closures N9 (9mm) 2ml vials and closures are universally suitable on most autosamplers, convenient in handling and available in a broad selection of different cap colors and septum materials.