Autosampler Vials & Caps for HPLC & GC | Thermo Fisher . Standard 2 mL screw top vial-cap kits; including. SureStop vials with AVCS caps. 4, 8, 12, 16, 20, or 40 mL vial-cap kits. 20 mL glass screw top vials with 24 mm caps. Innovative technology ensures proper vial-cap seal every time. For use with environmental analyses under EPA regulations.