Screw Top Vials, Caps and Kits | Thermo Fisher Scientific. Screw thread vials & closures for HPLC, GC, MS applications There’s a Thermo Scientific screw top vial for every HPLC, GC, MS instrument, application, and budget. Our screw top clear and amber glass vials and plastic screw top vials are available in 8mm, 9mm.