Crimp Top Vials are one of several vial types used in autosamplers for automated sample injection into HPLC, GC, and MS analytical instruments. Autosampler Vials & Caps for HPLC & GC - Thermo Fisher Scientific Headspace vials with 20 mm crimp tops and 18 mm screw tops in sizes ranging from 6 mL to 20 mL are available in clear or amber glass.