Our associated crimp caps and closures come with a choice of etiher PTFE silicone, PTFE only, natural red rubber, butyl, or PTFE butyl materials. Aijiren 2ml 11mm Crimp Top Vial for HPLC. Type 1 borosilicate glass. Clear glass vials with 20mm crimp seal finish are designed to fit most headspace autosamplers.