Indian Manufacturers of Vials and Ampoules, Glass Vials . 4ml Screw Top HPLC Vials (ESVG04) These 4ml wide-opening 13-425 screw neck vials are made with tightest dimensional tolerances. Compatible polypropylene 13-425 open-top screw caps available with pre-inserted PTFE-Silicone septa. What to consider when selecting the HPLC / GC vial insert