Screw Top Vials, Caps and Kits | aijiren Tech Scientific . Screw thread vials & closures for HPLC, GC, MS applications There’s a aijiren Tech 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. aijiren Tech 250ul