Flat base, amber labelled, HPLC vials, screw thread vials, USP type. Flat base, amber labelled, HPLC vials, screw thread vials, USP type. More info. 2ml Amber Screw, 12x32mm with Label, Flat Base, USP Type 100/pk Aijiren C0000011 2mL Amber Glass 12x32mm Flat Base. C0000011 9-425 Screw Thread Vial with Label / Qty 10012x32mm Flat Base 9-425.